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Sample records for rankin scale secondary

  1. Experimental and Thermoeconomic Analysis of Small-Scale Solar Organic Rankine Cycle (SORC System

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    Suresh Baral

    2015-04-01

    Full Text Available A small-scale solar organic Rankine cycle (ORC is a promising renewable energy-driven power generation technology that can be used in the rural areas of developing countries. A prototype was developed and tested for its performance characteristics under a range of solar source temperatures. The solar ORC system power output was calculated based on the thermal and solar collector efficiency. The maximum solar power output was observed in April. The solar ORC unit power output ranged from 0.4 kW to 1.38 kW during the year. The highest power output was obtained when the expander inlet pressure was 13 bar and the solar source temperature was 120 °C. The area of the collector for the investigation was calculated based on the meteorological conditions of Busan City (South Korea. In the second part, economic and thermoeconomic analyses were carried out to determine the cost of energy per kWh from the solar ORC. The selling price of electricity generation was found to be $0.68/kWh and $0.39/kWh for the prototype and low cost solar ORC, respectively. The sensitivity analysis was carried out in order to find the influencing economic parameters for the change in NPV. Finally, the sustainability index was calculated to assess the sustainable development of the solar ORC system.

  2. Exergy analysis of micro-organic Rankine power cycles for a small scale solar driven reverse osmosis desalination system

    Energy Technology Data Exchange (ETDEWEB)

    Tchanche, B.F.; Lambrinos, Gr.; Frangoudakis, A.; Papadakis, G. [Department of Natural Resources and Agricultural Engineering, Agricultural University of Athens, 75 Iera Odos Street, 11855 Athens (Greece)

    2010-04-15

    Exergy analysis of micro-organic Rankine heat engines is performed to identify the most suitable engine for driving a small scale reverse osmosis desalination system. Three modified engines derived from simple Rankine engine using regeneration (incorporation of regenerator or feedliquid heaters) are analyzed through a novel approach, called exergy-topological method based on the combination of exergy flow graphs, exergy loss graphs, and thermoeconomic graphs. For the investigations, three working fluids are considered: R134a, R245fa and R600. The incorporated devices produce different results with different fluids. Exergy destruction throughout the systems operating with R134a was quantified and illustrated using exergy diagrams. The sites with greater exergy destruction include turbine, evaporator and feedliquid heaters. The most critical components include evaporator, turbine and mixing units. A regenerative heat exchanger has positive effects only when the engine operates with dry fluids; feedliquid heaters improve the degree of thermodynamic perfection of the system but lead to loss in exergetic efficiency. Although, different modifications produce better energy conversion and less exergy destroyed, the improvements are not significant enough and subsequent modifications of the simple Rankine engine cannot be considered as economically profitable for heat source temperature below 100 C. As illustration, a regenerator increases the system's energy efficiency by 7%, the degree of thermodynamic perfection by 3.5% while the exergetic efficiency is unchanged in comparison with the simple Rankine cycle, with R600 as working fluid. The impacts of heat source temperature and pinch point temperature difference on engine's performance are also examined. Finally, results demonstrate that energy analysis combined with the mathematical graph theory is a powerful tool in performance assessments of Rankine based power systems and permits meaningful comparison of

  3. Association between Cerebral Performance Category, Modified Rankin Scale, and discharge disposition after cardiac arrest.

    Science.gov (United States)

    Rittenberger, Jon C; Raina, Ketki; Holm, Margo B; Kim, Young Joo; Callaway, Clifton W

    2011-08-01

    Cerebral Performance Category (CPC), Modified Rankin Scale (mRS) and discharge disposition are commonly used to determine outcomes following cardiac arrest. This study tested the association between these outcome measures. Retrospective chart review of subjects who survived to hospital discharge between 1/1/2006 and 12/31/2009 was conducted. Charts were reviewed for outcomes (CPC, mRS, and discharge disposition). Discharge disposition was classified in 6 categories: home with no services, home with home healthcare, acute rehabilitation facility, skilled nursing facility, long term acute care facility, and hospice. Intra-and inter-rater reliabilities were calculated for outcome measures. Rates of "good outcome" (defined as a CPC of 1-2, mRS of 0-3, or discharge disposition to home or acute rehabilitation facility) were also determined. Kendall's tau correlation coefficients explored relationships among measures. A total of 211 charts were reviewed. Mean age was 60 years (SD 16), the majority (75%) were white males, in- and out-of hospital cardiac arrests were equally prevalent, and ventricular dysrhythmia was most common (N=109, 52%). Half of the subjects were comatose following resuscitation and 75 (35%) received therapeutic hypothermia. Inter-rater percentage agreement for CPC and mRS abstraction was 95.24% (kappa 0.89, pdefinition, 47 subjects (22%) using the mRS definition, and 129 subjects (61%) subjects using discharge disposition definition. There was fair relationship between the CPC and mRS (tau 0.43) and poor relationships between CPC and discharge disposition (tau 0.23) and between mRS and discharge disposition (tau 0.25). Determination of the CPC, mRS and discharge disposition at hospital discharge is reliable from chart review. These instruments provide widely differing estimates of "good outcome". Agreement between these measures ranges from poor to fair. A more nuanced outcome measure designed for the post-cardiac arrest population is needed

  4. Conversion of Low Quality Waste Heat to Electric Power with Small-Scale Organic Rankine Cycle (ORC) Engine/Generator Technology

    Science.gov (United States)

    2016-08-01

    Small-Scale W912H0-12-C-0059 Organic Rankine Cycle (ORC) Engine /Generator Technology 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR( SI 5d...same fuel input. This value is used for calculation of Greenhouse Gas (GHG) reductions and economic results. Life cycle economics of the system are...associated with engine and other electric generator systems , waste heat from steam or heat distribution, waste heat from boiler exhausts, and heat

  5. Prediction of two month modified Rankin Scale with an ordinal prediction model in patients with aneurysmal subarachnoid haemorrhage

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    Sneade Mary

    2010-09-01

    Full Text Available Abstract Background Aneurysmal subarachnoid haemorrhage (aSAH is a devastating event with a frequently disabling outcome. Our aim was to develop a prognostic model to predict an ordinal clinical outcome at two months in patients with aSAH. Methods We studied patients enrolled in the International Subarachnoid Aneurysm Trial (ISAT, a randomized multicentre trial to compare coiling and clipping in aSAH patients. Several models were explored to estimate a patient's outcome according to the modified Rankin Scale (mRS at two months after aSAH. Our final model was validated internally with bootstrapping techniques. Results The study population comprised of 2,128 patients of whom 159 patients died within 2 months (8%. Multivariable proportional odds analysis identified World Federation of Neurosurgical Societies (WFNS grade as the most important predictor, followed by age, sex, lumen size of the aneurysm, Fisher grade, vasospasm on angiography, and treatment modality. The model discriminated moderately between those with poor and good mRS scores (c statistic = 0.65, with minor optimism according to bootstrap re-sampling (optimism corrected c statistic = 0.64. Conclusion We presented a calibrated and internally validated ordinal prognostic model to predict two month mRS in aSAH patients who survived the early stage up till a treatment decision. Although generalizability of the model is limited due to the selected population in which it was developed, this model could eventually be used to support clinical decision making after external validation. Trial Registration International Standard Randomised Controlled Trial, Number ISRCTN49866681

  6. Preliminary Development of a Free Piston Expander–Linear Generator for Small-Scale Organic Rankine Cycle (ORC Waste Heat Recovery System

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    Gaosheng Li

    2016-04-01

    Full Text Available A novel free piston expander-linear generator (FPE-LG integrated unit was proposed to recover waste heat efficiently from vehicle engine. This integrated unit can be used in a small-scale Organic Rankine Cycle (ORC system and can directly convert the thermodynamic energy of working fluid into electric energy. The conceptual design of the free piston expander (FPE was introduced and discussed. A cam plate and the corresponding valve train were used to control the inlet and outlet valve timing of the FPE. The working principle of the FPE-LG was proven to be feasible using an air test rig. The indicated efficiency of the FPE was obtained from the p–V indicator diagram. The dynamic characteristics of the in-cylinder flow field during the intake and exhaust processes of the FPE were analyzed based on Fluent software and 3D numerical simulation models using a computation fluid dynamics method. Results show that the indicated efficiency of the FPE can reach 66.2% and the maximal electric power output of the FPE-LG can reach 22.7 W when the working frequency is 3 Hz and intake pressure is 0.2 MPa. Two large-scale vortices are formed during the intake process because of the non-uniform distribution of velocity and pressure. The vortex flow will convert pressure energy and kinetic energy into thermodynamic energy for the working fluid, which weakens the power capacity of the working fluid.

  7. Energy, Exergy and Economic Evaluation Comparison of Small-Scale Single and Dual Pressure Organic Rankine Cycles Integrated with Low-Grade Heat Sources

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    Armando Fontalvo

    2017-09-01

    Full Text Available Low-grade heat sources such as solar thermal, geothermal, exhaust gases and industrial waste heat are suitable alternatives for power generation which can be exploited by means of small-scale Organic Rankine Cycle (ORC. This paper combines thermodynamic optimization and economic analysis to assess the performance of single and dual pressure ORC operating with different organic fluids and targeting small-scale applications. Maximum power output is lower than 45 KW while the temperature of the heat source varies in the range 100–200 °C. The studied working fluids, namely R1234yf, R1234ze(E and R1234ze(Z, are selected based on environmental, safety and thermal performance criteria. Levelized Cost of Electricity (LCOE and Specific Investment Cost (SIC for two operation conditions are presented: maximum power output and maximum thermal efficiency. Results showed that R1234ze(Z achieves the highest net power output (up to 44 kW when net power output is optimized. Regenerative ORC achieves the highest performance when thermal efficiency is optimized (up to 18%. Simple ORC is the most cost-effective among the studied cycle configurations, requiring a selling price of energy of 0.3 USD/kWh to obtain a payback period of 8 years. According to SIC results, the working fluid R1234ze(Z exhibits great potential for simple ORC when compared to conventional R245fa.

  8. Experimental Assessment of a Helical Coil Heat Exchanger Operating at Subcritical and Supercritical Conditions in a Small-Scale Solar Organic Rankine Cycle

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    Marija Lazova

    2017-05-01

    Full Text Available In this study, the performance of a helical coil heat exchanger operating at subcritical and supercritical conditions is analysed. The counter-current heat exchanger was specially designed to operate at a maximal pressure and temperature of 42 bar and 200 °C, respectively. The small-scale solar organic Rankine cycle (ORC installation has a net power output of 3 kWe. The first tests were done in a laboratory where an electrical heater was used instead of the concentrated photovoltaic/thermal (CPV/T collectors. The inlet heating fluid temperature of the water was 95 °C. The effects of different parameters on the heat transfer rate in the heat exchanger were investigated. Particularly, the performance analysis was elaborated considering the changes of the mass flow rate of the working fluid (R-404A in the range of 0.20–0.33 kg/s and the inlet pressure varying from 18 bar up to 41 bar. Hence, the variation of the heat flux was in the range of 5–9 kW/m2. The results show that the working fluid’s mass flow rate has significant influence on the heat transfer rate rather than the operational pressure. Furthermore, from the comparison between the experimental results with the heat transfer correlations from the literature, the experimental results fall within the uncertainty range for the supercritical analysis but there is a deviation of the investigated subcritical correlations.

  9. Low-Concentration Solar-Power Systems based on Organic Rankine Cycles for Distributed-Scale Applications:Overview and Further Developments

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    Christos N. Markides

    2015-12-01

    Full Text Available This paper is concerned with the emergence and development of low- to medium-grade thermal-energy conversion systems for distributed power generation based on thermodynamic vapour-phase heat-engine cycles undergone by organic working-fluids, namely organic Rankine cycles (ORCs. ORC power systems are, to some extent, a relatively established and mature technology that is well-suited to converting low-/medium-grade heat (at temperatures up to ~ 300 – 400 °C to useful work, at an output power scale from a few kW to 10s of MW. Thermal efficiencies in excess of 25% are achievable at higher temperatures and larger scales, and efforts are currently in progress to improve the overall economic viability, and thus uptake, of ORC power systems by focusing on advanced architectures, working-fluid selection, heat exchangers and expansion machines. Solar-power systems based on ORC technology have a significant potential to be used for distributed power generation, by converting thermal energy from simple and low-cost non-concentrated or low-concentration collectors to mechanical, hydraulic or electrical energy. Current fields of use include mainly geothermal and biomass/biogas, as well as the recovery and conversion of waste heat, leading to improved energy efficiency, primary energy (i.e. fuel use and emission minimization, yet the technology is highly transferable to solar power generation as an affordable alternative to small- to medium-scale photovoltaic (PV systems. Solar-ORC systems offer naturally the advantages of providing a simultaneous thermal-energy output for hot water provision and/or space heating, and the particularly interesting possibility of relatively straightforward on-site (thermal energy storage. Key performance characteristics are presented, and important heat transfer effects that act to limit performance are identified as noteworthy directions of future research for the further development of this technology.

  10. Capillary Transit Time Heterogeneity Is Associated with Modified Rankin Scale Score at Discharge in Patients with Bilateral High Grade Internal Carotid Artery Stenosis.

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    Sibu Mundiyanapurath

    Full Text Available Perfusion weighted imaging (PWI is inherently unreliable in patients with severe perfusion abnormalities. We compared the diagnostic accuracy of a novel index of microvascular flow-patterns, so-called capillary transit time heterogeneity (CTH to that of the commonly used delay parameter Tmax in patients with bilateral high grade internal carotid artery stenosis (ICAS.Consecutive patients with bilateral ICAS ≥ 70%NASCET who underwent PWI were retrospectively examined. Maps of CTH and Tmax were analyzed with a volumetric approach using several thresholds. Predictors of favorable outcome (modified Rankin scale at discharge 0-2 were identified using univariate and receiver operating characteristic (ROC curve analysis.Eighteen patients were included. CTH ≥ 30s differentiated best between patients with favorable and unfavorable outcome when both hemispheres were taken into account (sensitivity 83%, specificity 73%, area under the curve [AUC] 0.833 [confidence interval (CI 0.635; 1.000]; p = 0.027. The best discrimination using Tmax was achieved with a threshold of ≥ 4s (sensitivity 83%, specificity 64%, AUC 0.803 [CI 0.585;1.000]; p = 0.044. The highest AUC was found for left sided volume with CTH ≥ 15s (sensitivity 83%, specificity 91%, AUC 0.924 [CI 0.791;1.000]; p = 0.005.The study suggests that CTH is superior to Tmax in discriminating ICAS patients with favorable from non-favorable outcome. This finding may reflect the simultaneous involvement of large vessels and microvessels in ICAS and underscore the need to diagnose and manage both aspects of the disease.

  11. Ichthyosiform scaling secondary to megavoltage radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Ross, E.V. (National Naval Medical Center, Bethesda, MD (USA))

    1991-07-01

    Acquired ichthyosis is a rare dermatosis associated with a number of malignancies. Side effects seen on the skin secondary to megavoltage radiotherapy are uncommon but may include fine dry desquamation and tanning. The authors present a case of ichthyosiform scaling limited to the radiation fields in a patient treated for brain metastases of a primary small cell lung carcinoma. The reader is reminded that side effects of megavoltage treatment do occur on the skin. A brief review of these effects is included. 5 references.

  12. Working Fluid Stability in Large-Scale Organic Rankine Cycle-Units Using Siloxanes—Long-Term Experiences and Fluid Recycling

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    Tobias G. Erhart

    2016-05-01

    Full Text Available The results in this work show the influence of long-term operation on the decomposition of working fluids in eight different organic rankine cycle (ORC power plants (both heat-led and electricity-led in a range of 900 kW el to 2 MW el . All case study plants are using octamethyltrisiloxane (MDM as a working fluid; the facilities are between six to 12 years old. Detailed analyses, including the fluid distribution throughout the cycle, are conducted on one system. All presented fluid samples are analyzed via head space gas chromatography mass spectrometry (HS-GC-MS. Besides the siloxane composition, the influence of contaminants, such as mineral oil-based lubricants (and their components, is examined. In most cases, the original working fluid degrades to fractions of siloxanes with a lower boiling point (low boilers and fractions with a higher boiling point (high boilers. As a consequence of the analyses, a new fluid recycling and management system was designed and tested in one case study plant (Case Study #8. Pre-post comparisons of fluid samples prove the effectiveness of the applied methods. The results show that the recovery of used working fluid offers an alternative to the purchase of fresh fluid, since operating costs can be significantly reduced. For large facilities, the prices for new fluid range from € 15 per liter (in 2006 to € 22 per liter (in 2013, which is a large reinvestment, especially in light of filling volumes of 4000 liters to 7000 liters per unit. Using the aforementioned method, a price of € 8 per liter of recovered MDM can be achieved.

  13. Derivation and Validation of a Novel Prognostic Scale (Modified-Stroke Subtype, Oxfordshire Community Stroke Project Classification, Age, and Prestroke Modified Rankin) to Predict Early Mortality in Acute Stroke.

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    Abdul-Rahim, Azmil H; Quinn, Terence J; Alder, Sarah; Clark, Allan B; Musgrave, Stanley D; Langhorne, Peter; Potter, John F; Myint, Phyo Kyaw

    2016-01-01

    The stroke subtype, Oxfordshire Community Stroke Project classification, age, and prestroke modified Rankin (SOAR) score is a prognostic scale proposed for early mortality prediction after acute stroke. We aimed to evaluate whether including a measure of initial stroke severity (National Institutes of Health Stroke Scale and modified-SOAR [mSOAR] scores) would improve the prognostic accuracy. Using Anglia Stroke and Heart Clinical Network data, 2008 to 2011, we assessed the performance of SOAR and mSOAR against in-hospital mortality using area under the receiver operating curve statistics. We externally validated the prognostic utility of SOAR and mSOAR using an independent cohort data set from Glasgow. We described calibration using Hosmer-Lemeshow goodness-of-fit test. A total of 1002 patients were included in the derivation cohort, and 105 (10.5%) died as inpatients. The area under the receiver operating curves for outcome of early mortality derived from the SOAR and mSOAR scores were 0.79 (95% confidence interval, 0.75-0.84) and 0.83 (95% confidence interval, 0.79-0.86), respectively (P=0.001). The external validation data set contained 1012 patients with stroke; of which, 121 (12.0%) patients died within 90 days. The mSOAR scores identified the risk of early mortality ranging from 3% to 42%. External validation of mSOAR score yielded an area under the receiver operating curve of 0.84 (95% confidence interval, 0.82-0.88) for outcome of early mortality. Calibration was good (P=0.70 for the Hosmer-Lemeshow test). Adding National Institutes of Health Stroke Scale data to create a modified-SOAR score improved prognostic utility in both derivation and validation data sets. The mSOAR may have clinical utility by using easily available data to predict mortality. © 2015 American Heart Association, Inc.

  14. Performance analysis a of solar driven organic Rankine cycle using multi-component working fluids

    DEFF Research Database (Denmark)

    Baldasso, E.; Andreasen, J. G.; Modi, A.

    2015-01-01

    Among the different renewable sources of energy, solar power could play a primary role in the development of a more sustainable electricity generation system. While large scale concentrated solar power plants based on the steam Rankine cycle have already been proved to be cost effective, research...... is still under progress for small scale low temperature solar-driven power plants. The steam Rankine cycle is suitable for high temperature applications, but its efficiency drastically decreases as the heat source temperature drops. In these cases a much more promising configuration is the organic Rankine...... field made of parabolic trough collectors and a recuperative organic Rankine cycle. Pressurized water is selected as heat transfer fluid and its maximum temperature is fixed to 150°C. The target power output for the plant is 100 kWel. A part load analysis is carried out in order to define the most...

  15. Rankine-cycle solar-cooling systems

    Science.gov (United States)

    Weathers, H. M.

    1979-01-01

    Report reviews progress made by three contractors to Marshall Space Flight Center and Department of Energy in developing Rankine-cycle machines for solar cooling and testing of commercially available equipment involved.

  16. Organic Rankine Cycles. Old wine in new bottles; Organic Rankine Cycles. Oude wijn in nieuwe zakken

    Energy Technology Data Exchange (ETDEWEB)

    Den Hartog, T.L.B. [Cumae, Arnhem (Netherlands)

    2007-05-15

    An overview is given of the renewed interest for the Organic Rankine Cycle technology and new developments with regard to this power generating technology. [Dutch] Een overzicht wordt gegeven van de hernieuwde belangstelling voor de Organic Rankine Cycle (ORC) technologie en nieuwe ontwikkeling m.b.t. deze vorm van elektriciteitopwekking.

  17. Cascaded organic rankine cycles for waste heat utilization

    Science.gov (United States)

    Radcliff, Thomas D [Vernon, CT; Biederman, Bruce P [West Hartford, CT; Brasz, Joost J [Fayetteville, NY

    2011-05-17

    A pair of organic Rankine cycle systems (20, 25) are combined and their respective organic working fluids are chosen such that the organic working fluid of the first organic Rankine cycle is condensed at a condensation temperature that is well above the boiling point of the organic working fluid of the second organic Rankine style system, and a single common heat exchanger (23) is used for both the condenser of the first organic Rankine cycle system and the evaporator of the second organic Rankine cycle system. A preferred organic working fluid of the first system is toluene and that of the second organic working fluid is R245fa.

  18. Optimal design of compact organic Rankine cycle units for domestic solar applications

    DEFF Research Database (Denmark)

    Barbazza, Luca; Pierobon, Leonardo; Mirandola, Alberto

    2014-01-01

    Organic Rankine cycle turbogenerators are a promising technology to transform the solar radiation harvested by solar collectors into electric power. The present work aims at sizing a small-scale organic Rankine cycle unit by tailoring its design for domestic solar applications. Stringent design...... solar collectors (hot water temperature equal to 75 degrees C), R1234yf is the optimal solution. The heat exchanger volume ranges between 6.0 and 23.0 dm(3), whereas the thermal efficiency is around 4.5%. R1234ze is the best working fluid employing parabolic solar collectors (hot water temperature equal...

  19. Affordable Rankine Cycle Waste Heat Recovery for Heavy Duty Trucks

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, Swami Nathan [Eaton Corporation

    2017-06-30

    Nearly 30% of fuel energy is not utilized and wasted in the engine exhaust. Organic Rankine Cycle (ORC) based waste heat recovery (WHR) systems offer a promising approach on waste energy recovery and improving the efficiency of Heavy-Duty diesel engines. Major barriers in the ORC WHR system are the system cost and controversial waste heat recovery working fluids. More than 40% of the system cost is from the additional heat exchangers (recuperator, condenser and tail pipe boiler). The secondary working fluid loop designed in ORC system is either flammable or environmentally sensitive. The Eaton team investigated a novel approach to reduce the cost of implementing ORC based WHR systems to Heavy-Duty (HD) Diesel engines while utilizing safest working fluids. Affordable Rankine Cycle (ARC) concept aimed to define the next generation of waste energy recuperation with a cost optimized WHR system. ARC project used engine coolant as the working fluid. This approach reduced the need for a secondary working fluid circuit and subsequent complexity. A portion of the liquid phase engine coolant has been pressurized through a set of working fluid pumps and used to recover waste heat from the exhaust gas recirculation (EGR) and exhaust tail pipe exhaust energy. While absorbing heat, the mixture is partially vaporized but remains a wet binary mixture. The pressurized mixed-phase engine coolant mixture is then expanded through a fixed-volume ratio expander that is compatible with two-phase conditions. Heat rejection is accomplished through the engine radiator, avoiding the need for a separate condenser. The ARC system has been investigated for PACCAR’s MX-13 HD diesel engine.

  20. Toluene stability Space Station Rankine power system

    Science.gov (United States)

    Havens, V. N.; Ragaller, D. R.; Sibert, L.; Miller, D.

    1987-01-01

    A dynamic test loop is designed to evaluate the thermal stability of an organic Rankine cycle working fluid, toluene, for potential application to the Space Station power conversion unit. Samples of the noncondensible gases and the liquid toluene were taken periodically during the 3410 hour test at 750 F peak temperature. The results obtained from the toluene stability loop verify that toluene degradation will not lead to a loss of performance over the 30-year Space Station mission life requirement. The identity of the degradation products and the low rates of formation were as expected from toluene capsule test data.

  1. Organic rankine cycle waste heat applications

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    Brasz, Joost J.; Biederman, Bruce P.

    2007-02-13

    A machine designed as a centrifugal compressor is applied as an organic rankine cycle turbine by operating the machine in reverse. In order to accommodate the higher pressures when operating as a turbine, a suitable refrigerant is chosen such that the pressures and temperatures are maintained within established limits. Such an adaptation of existing, relatively inexpensive equipment to an application that may be otherwise uneconomical, allows for the convenient and economical use of energy that would be otherwise lost by waste heat to the atmosphere.

  2. Energy analysis of Organic Rankine Cycles for biomass applications

    Directory of Open Access Journals (Sweden)

    Algieri Angelo

    2015-01-01

    Full Text Available The present paper aims at analysing the performances of Organic Rankine Cycles (ORCs adopted for the exploitation of the biomass resulting from the pruning residues in a 3000 hectares district in Southern Italy. A parametric energy analysis has been carried out to define the influence of the main plant operating conditions. To this purpose, both subcritical and transcritical power plants have been examined and saturated and superheated conditions at the turbine inlet have been imposed. Moreover, the effect of the working fluid, condensation temperature, and internal regeneration on system performances has been investigated. The results show that ORC plants represent an interesting and sustainable solution for decentralised and small-scale power production. Furthermore, the analysis highlights the significant impact of the maximum temperature and the noticeable effect of internal regeneration on the performances of the biomass power plants.

  3. Scale, heterogeneity and secondary production in tropical rangelands

    African Journals Online (AJOL)

    This paper will review our current understanding of scale-related effects on livestock production in tropical rangelands and herbivore-plant interactions at patch to landscape scales. We use published information and results from recent empirical studies in northern Australia and elsewhere to elucidate scale-related effects ...

  4. SORCE: A design tool for solar organic Rankine cycle systems in distributed generation applications

    OpenAIRE

    Orosz, Matthew; Quoilin, Sylvain; Hemond, Harold

    2010-01-01

    Recent interest in small-scale solar thermal combined heat and power (CHP) power systems has coincided with demand growth for distributed electricity supplies in areas poorly served by centralized power stations. One potential technical approach to meeting this demand is the parabolic trough solar thermal collector coupled with an organic Rankine cycle (ORC) heat engine. Much existing research touches on aspects of the underlying physics and mechanics of this technology, but a holistic treatm...

  5. A Validity Study of Attitudes toward Science Scale among Iranian Secondary School Students

    Science.gov (United States)

    Liaghatdar, Muhammad J.; Soltani, Asghar; Abedi, Ahmad

    2011-01-01

    The purpose of this study is providing a scale for measuring attitudes toward science among Persian secondary school students. A total of 300 (150 girls and 150 boys) of second grade students from all disciplines including science and mathematics in secondary education, participated in the study. Research instrument was, translated Persian version…

  6. Deriving modified Rankin scores from medical case-records.

    Science.gov (United States)

    Quinn, Terence J; Ray, Gautamananda; Atula, Sari; Walters, Matthew R; Dawson, Jesse; Lees, Kennedy R

    2008-12-01

    Modified Rankin score (mRS) is traditionally graded using a face-to-face or telephone interview. Certain stroke assessment scales can be derived from a review of a patient's case-record alone. We hypothesized that mRS could be successfully derived from the narrative within patient case-records. Sequential patients attending our cerebrovascular outpatient clinic were included. Two independent, blinded clinicians, trained in mRS, assessed case-records to derive mRS. They scored "certainty" of their grading on a 5-point Likert scale. Agreement between derived and traditional face-to-face mRS was calculated using attribute agreement analysis. Fifty patients with a range of disabilities were included. Case-record appraisers were poor at deriving mRS (k=0.34 against standard). Derived mRS grades showed poor agreement between observers (k=0.33). There was no relationship between certainty of derived mRS and proportion of correct grades (P=0.727). Accurate mRS cannot be derived from standard hospital records. Direct mRS interview is still required for clinical trials.

  7. Secondary Aluminum Melting Research in a Laboratory Scale Reverberatory Furnace

    Energy Technology Data Exchange (ETDEWEB)

    Clark, J.A., III

    2003-01-01

    The Albany Research Center (ARC), U.S. Department of Energy, has developed a 175-pound capacity, natural gas, direct-fired reverberatory furnace. The high temperature reactions present during the aluminum remelt process are being investigated. Preventing dross formation has been the key aim to date. Reducing losses to dross by 25-50% will potentially lead to an annual energy savings of over 75 trillion BTU's by the year 2020. Schematics and operation characteristics of the ARC Laboratory Scale Reverberatory Furnace (LSRF) will be presented. Potential gas-solid, gas-liquid, and liquid-solid interactions between the hot combustion gases, aluminum, and refractories will be discussed.

  8. The dish-Rankine SCSTPE program (Engineering Experiment no. 1)

    Science.gov (United States)

    Pons, R. L.; Grigsby, C. E.

    1980-05-01

    Activities planned for phase 2 Of the Small Community Solar Thermal Power Experiment (PFDR) program are summarized with emphasis on a dish-Rankine point focusing distributed receiver solar thermal electric system. Major design efforts include: (1) development of an advanced concept indirect-heated receiver;(2) development of hardware and software for a totally unmanned power plant control system; (3) implementation of a hybrid digital simulator which will validate plant operation prior to field testing; and (4) the acquisition of an efficient organic Rankine cycle power conversion unit. Preliminary performance analyses indicate that a mass-produced dish-Rankine PFDR system is potentially capable of producing electricity at a levelized busbar energy cost of 60 to 70 mills per KWh and with a capital cost of about $1300 per KW.

  9. Emissions-critical charge cooling using an organic rankine cycle

    Science.gov (United States)

    Ernst, Timothy C.; Nelson, Christopher R.

    2014-07-15

    The disclosure provides a system including a Rankine power cycle cooling subsystem providing emissions-critical charge cooling of an input charge flow. The system includes a boiler fluidly coupled to the input charge flow, an energy conversion device fluidly coupled to the boiler, a condenser fluidly coupled to the energy conversion device, a pump fluidly coupled to the condenser and the boiler, an adjuster that adjusts at least one parameter of the Rankine power cycle subsystem to change a temperature of the input charge exiting the boiler, and a sensor adapted to sense a temperature characteristic of the vaporized input charge. The system includes a controller that can determine a target temperature of the input charge sufficient to meet or exceed predetermined target emissions and cause the adjuster to adjust at least one parameter of the Rankine power cycle to achieve the predetermined target emissions.

  10. Analysis of Low Temperature Organic Rankine Cycles for Solar Applications

    Science.gov (United States)

    Li, Yunfei

    The present work focuses on Organic Rankine Cycle (ORC) systems and their application to low temperature waste heat recovery, combined heat and power as well as off-grid solar power generation applications. As CO_2 issues come to the fore front and fossil fuels become more expensive, interest in low grade heat recovery has grown dramatically in the past few years. Solar energy, as a clean, renewable, pollution-free and sustainable energy has great potential for the use of ORC systems. Several ORC solutions have been proposed to generate electricity from low temperature sources. The ORC systems discussed here can be applied to fields such as solar thermal, biological waste heat, engine exhaust gases, small-scale cogeneration, domestic boilers, etc. The current work presents a thermodynamic and economic analysis for the use of ORC systems to convert solar energy or low exergy energy to generate electrical power. The organic working fluids investigated here were selected to investigate the effect of the fluid saturation temperature on the performance of ORCs. The working fluids under investigation are R113, R245fa, R123, with boiling points between 40°C and 200°C at pressures from 10 kPa to 10 MPa. Ambient temperature air at 20oC to 30oC is utilized as cooling resource, and allowing for a temperature difference 10°C for effective heat transfer. Consequently, the working fluids are condensed at 40°C. A combined first- and second-law analysis is performed by varying some system independent parameters at various reference temperatures. The present work shows that ORC systems can be viable and economical for the applications such as waste heat use and off-grid power generation even though they are likely to be more expensive than grid power.

  11. Organic Rankine Cycle with Solar Heat Storage in Paraffin Way

    Directory of Open Access Journals (Sweden)

    Constantin LUCA

    2015-06-01

    Full Text Available The paper presents an electricity generation system based on an Organic Rankine Cycle and proposed storing the amount of the heat produced by the solar panels using large volume of paraffin wax. The proposed working fluid is R-134a refrigerant. The cycle operates at very low temperatures. A efficiency of 6,55% was obtained.

  12. Full-scale performance assessment of aircraft secondary sandwich structure using thermoelastic stress analysis

    OpenAIRE

    Crump, D.A.; Dulieu-Barton, J.M.; Savage, J

    2009-01-01

    The use of resin film infusion (RFI) has been proven to reduce the cost of production of aircraft secondary sandwich structure. In this paper thermoelastic stress analysis (TSA) is used to assess the performance of full scale aircraft sandwich structure panels produced using both the conventional autoclave process and RFI. Finite element (FE) models of both panel types are developed and TSA is used to validate the models.

  13. Rankine-Brayton engine powered solar thermal aircraft

    Science.gov (United States)

    Bennett, Charles L [Livermore, CA

    2009-12-29

    A solar thermal powered aircraft powered by heat energy from the sun. A Rankine-Brayton hybrid cycle heat engine is carried by the aircraft body for producing power for a propulsion mechanism, such as a propeller or other mechanism for enabling sustained free flight. The Rankine-Brayton engine has a thermal battery, preferably containing a lithium-hydride and lithium mixture, operably connected to it so that heat is supplied from the thermal battery to a working fluid. A solar concentrator, such as reflective parabolic trough, is movably connected to an optically transparent section of the aircraft body for receiving and concentrating solar energy from within the aircraft. Concentrated solar energy is collected by a heat collection and transport conduit, and heat transported to the thermal battery. A solar tracker includes a heliostat for determining optimal alignment with the sun, and a drive motor actuating the solar concentrator into optimal alignment with the sun based on a determination by the heliostat.

  14. Beyond the Burke-Fahn-Marsden Dystonia Rating Scale: deep brain stimulation in childhood secondary dystonia.

    Science.gov (United States)

    Gimeno, Hortensia; Tustin, Kylee; Selway, Richard; Lin, Jean-Pierre

    2012-09-01

    Deep brain stimulation is now widely accepted as an effective treatment for children with primary generalized dystonia. More variable results are reported in secondary dystonias and its efficacy in this heterogeneous group has not been fully elucidated. Deep brain stimulation outcomes are typically reported using impairment-focused measures, such as the Burke-Fahn-Marsden Dystonia Rating Scale, which provide little information about function and participation outcomes or changes in non-motor areas. The aim is to demonstrate that in some cases of secondary dystonia, the sole use of impairment level measures, such as the Burke-Fahn-Marsden Dystonia Rating Scale, may be insufficient to fully evaluate outcome following deep brain stimulation. Six paediatric cases who underwent deep brain stimulation surgery with a minimum of one year follow up were selected on the basis of apparent non-response to deep brain stimulation, defined as a clinically insignificant change in the Burke-Fahn-Marsden Dystonia Movement Scale (stimulation, parallel outcome measures demonstrated significant benefit in a range of child and family-centred goal areas including: pain and comfort, school attendance, seating tolerance, access to assistive technology and in some cases carer burden. Sole use of impairment-focused measures, are limited in scope to evaluate outcome following deep brain stimulation, particularly in secondary dystonias. Systematic study of effects across multiple dimensions of disability is needed to determine what deep brain stimulation offers patients in terms of function, participation, care, comfort and quality of life. Deep brain stimulation may offer meaningful change across multiple domains of functioning, disability and health even in the absence of significant change in dystonia rating scales. Copyright © 2012 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved.

  15. Large-scale co-expression approach to dissect secondary cell wall formation across plant species

    Directory of Open Access Journals (Sweden)

    Colin eRuprecht

    2011-07-01

    Full Text Available Plant cell walls are complex composites largely consisting of carbohydrate-based polymers, and are generally divided into primary and secondary walls based on content and characteristics. Cellulose microfibrils constitute a major component of both primary and secondary cell walls and are synthesized at the plasma membrane by cellulose synthase (CESA complexes. Several studies in Arabidopsis have demonstrated the power of co-expression analyses to identify new genes associated with secondary wall cellulose biosynthesis. However, across-species comparative co-expression analyses remain largely unexplored. Here, we compared co-expressed gene vicinity networks of primary and secondary wall CESAs in Arabidopsis, barley, rice, poplar, soybean, Medicago and wheat, and identified gene families that are consistently co-regulated with cellulose biosynthesis. In addition to the expected polysaccharide acting enzymes, we also found many gene families associated with cytoskeleton, signaling, transcriptional regulation, oxidation and protein degradation. Based on these analyses, we selected and biochemically analyzed T-DNA insertion lines corresponding to approximately twenty genes from gene families that re-occur in the co-expressed gene vicinity networks of secondary wall CESAs across the seven species. We developed a statistical pipeline using principal component analysis (PCA and optimal clustering based on silhouette width to analyze sugar profiles. One of the mutants, corresponding to a pinoresinol reductase gene, displayed disturbed xylem morphology and held lower levels of lignin molecules. We propose that this type of large-scale co-expression approach, coupled with statistical analysis of the cell wall contents, will be useful to facilitate rapid knowledge transfer across plant species.

  16. Nano-Scale Secondary Ion Mass Spectrometry - A new analytical tool in biogeochemistry and soil ecology

    Energy Technology Data Exchange (ETDEWEB)

    Herrmann, A M; Ritz, K; Nunan, N; Clode, P L; Pett-Ridge, J; Kilburn, M R; Murphy, D V; O' Donnell, A G; Stockdale, E A

    2006-10-18

    Soils are structurally heterogeneous across a wide range of spatio-temporal scales. Consequently, external environmental conditions do not have a uniform effect throughout the soil, resulting in a large diversity of micro-habitats. It has been suggested that soil function can be studied without explicit consideration of such fine detail, but recent research has indicated that the micro-scale distribution of organisms may be of importance for a mechanistic understanding of many soil functions. Due to a lack of techniques with adequate sensitivity for data collection at appropriate scales, the question 'How important are various soil processes acting at different scales for ecological function?' is challenging to answer. The nano-scale secondary ion mass spectrometer (NanoSIMS) represents the latest generation of ion microprobes which link high-resolution microscopy with isotopic analysis. The main advantage of NanoSIMS over other secondary ion mass spectrometers is the ability to operate at high mass resolution, whilst maintaining both excellent signal transmission and spatial resolution ({approx}50 nm). NanoSIMS has been used previously in studies focusing on presolar materials from meteorites, in material science, biology, geology and mineralogy. Recently, the potential of NanoSIMS as a new tool in the study of biophysical interfaces in soils has been demonstrated. This paper describes the principles of NanoSIMS and discusses the potential of this tool to contribute to the field of biogeochemistry and soil ecology. Practical considerations (sample size and preparation, simultaneous collection of isotopes, mass resolution, isobaric interference and quantification of the isotopes of interest) are discussed. Adequate sample preparation avoiding biases in the interpretation of NanoSIMS data due to artifacts and identification of regions-of interest are of most concerns in using NanoSIMS as a new tool in biogeochemistry and soil ecology. Finally, we review

  17. Number theory and modular forms papers in memory of Robert A Rankin

    CERN Document Server

    Ono, Ken

    2003-01-01

    Robert A. Rankin, one of the world's foremost authorities on modular forms and a founding editor of The Ramanujan Journal, died on January 27, 2001, at the age of 85. Rankin had broad interests and contributed fundamental papers in a wide variety of areas within number theory, geometry, analysis, and algebra. To commemorate Rankin's life and work, the editors have collected together 25 papers by several eminent mathematicians reflecting Rankin's extensive range of interests within number theory. Many of these papers reflect Rankin's primary focus in modular forms. It is the editors' fervent hope that mathematicians will be stimulated by these papers and gain a greater appreciation for Rankin's contributions to mathematics. This volume would be an inspiration to students and researchers in the areas of number theory and modular forms.

  18. Performance of pilot-scale constructed wetlands for secondary treatment of chromium-bearing tannery wastewaters.

    Science.gov (United States)

    Dotro, Gabriela; Castro, Silvana; Tujchneider, Ofelia; Piovano, Nancy; Paris, Marta; Faggi, Ana; Palazolo, Paul; Larsen, Daniel; Fitch, Mark

    2012-11-15

    Tannery operations consist of converting raw animal skins into leather through a series of complex water- and chemically-intensive batch processes. Even when conventional primary treatment is supplemented with chemicals, the wastewater requires some form of biological treatment to enable the safe disposal to the natural environment. Thus, there is a need for the adoption of low cost, reliable, and easy-to-operate alternative secondary treatment processes. This paper reports the findings of two pilot-scale wetlands for the secondary treatment of primary effluents from a full tannery operation in terms of resilience (i.e., ability to produce consistent effluent quality in spite of variable influent loads) and reliability (i.e., ability to cope with sporadic shock loads) when treating this hazardous effluent. Areal mass removal rates of 77.1 g COD/m2/d, 11 g TSS/m2/d, and 53 mg Cr/m2/d were achieved with a simple gravity-flow horizontal subsurface flow unit operating at hydraulic loading rates of as much as 10 cm/d. Based on the findings, a full-scale wetland was sized to treat all the effluent from the tannery requiring 68% more land than would have been assumed based on literature values. Constructed wetlands can offer treatment plant resilience for minimum operational input and reliable effluent quality when biologically treating primary effluents from tannery operations. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Rethinking Racism in Claudia Rankine's Citizen: An American Lyric

    OpenAIRE

    Hersi, Asli

    2016-01-01

    The issue of race in America in the twenty-first century is still a turbulent matter. The end of segregation in schools, politics, marriages and workplaces created a mask that hid racial inequalities and injustices (Whitmarsh 1). In a time where police brutalities have frequently surfaced in the media in a supposed “post-racial America”, Claudia Rankine writes a thought-provoking 160 page long “book-length poem” about everyday racism arguing that the overlooking of microaggressions (brief dai...

  20. Rethinking Racism in Claudia Rankine's Citizen: An American Lyric

    OpenAIRE

    Hersi, Asli

    2016-01-01

    Master's thesis in Literacy studies The issue of race in America in the twenty-first century is still a turbulent matter. The end of segregation in schools, politics, marriages and workplaces created a mask that hid racial inequalities and injustices (Whitmarsh 1). In a time where police brutalities have frequently surfaced in the media in a supposed “post-racial America”, Claudia Rankine writes a thought-provoking 160 page long “book-length poem” about everyday racism arguing that the ove...

  1. Organic Rankine Cycle System Analysis for Low GWP Working Fluids

    OpenAIRE

    Datla, Bala Varma; Brasz, Joost

    2012-01-01

    The last decade has seen a substantial increase in Organic Rankine Cycle system installations for low temperature waste heat power recovery. The availability of HFC245fa has played a major role in this recent surge in ORC systems since it allows the use of existing HVAC hardware (heat exchangers and compressors) to be used as ORC components (turbines, boilers and condensers) with minimal redesign. The environmental drawback of HFC245fa is its relatively high GWP value of 950. The advent of a ...

  2. Full scale lightning surge tests of distribution transformers and secondary systems

    Energy Technology Data Exchange (ETDEWEB)

    Goedde, G.L.; Dugan, R.C. Sr.; Rowe, L.D. (Cooper Power Systems, Thomas A. Edison Technical Center, Franksville, WI (US))

    1992-07-01

    This paper reports that low-side surges are known to cause failures of distribution transformers. They also subject load devices to overvoltages. A full-scale model of a residential service has been set up in a laboratory and subjected to impulses approximating lightning strokes. The tests were made to determine the impulse characteristics of the secondary system and to test the validity of previous analyses. Among the variables investigated were stroke location, the balance of the surges in the service cable, and the effectiveness of arrester protection. Low-side surges were found to consist of two basic components: the natural frequency of the system and the inductive response of the system to the stoke current. The latter component is responsible for transformer failures while the former may be responsible for discharge spots often found around secondary bushings. Arresters at the service entrance are effective in diverting most of the energy from a lightning strike, but may not protect sensitive loads. Additional local protection is also needed. The tests affirmed previous simulations and uncovered additional phenomena as well.

  3. Time domain Rankine-Green panel method for offshore structures

    Science.gov (United States)

    Li, Zhifu; Ren, Huilong; Liu, Riming; Li, Hui

    2017-02-01

    To solve the numerical divergence problem of the direct time domain Green function method for the motion simulation of floating bodies with large flare, a time domain hybrid Rankine-Green boundary element method is proposed. In this numerical method, the fluid domain is decomposed by an imaginary control surface, at which the continuous condition should be satisfied. Then the Rankine Green function is adopted in the inner domain. The transient free surface Green function is applied in the outer domain, which is used to find the relationship between the velocity potential and its normal derivative for the inner domain. Besides, the velocity potential at the mean free surface between body surface and control surface is directly solved by the integration scheme. The wave exciting force is computed through the convolution integration with wave elevation, by introducing the impulse response function. Additionally, the nonlinear Froude-Krylov force and hydrostatic force, which is computed under the instantaneous incident wave free surface, are taken into account by the direct pressure integration scheme. The corresponding numerical computer code is developed and first used to compute the hydrodynamic coefficients of the hemisphere, as well as the time history of a ship with large flare; good agreement is obtained with the analytical solutions as well as the available numerical results. Then the hydrodynamic properties of a FPSO are studied. The hydrodynamic coefficients agree well with the results computed by the frequency method; the influence of the time interval and the truncated time is investigated in detail.

  4. Analysis of hot spots in boilers of organic Rankine cycle units during transient operation

    DEFF Research Database (Denmark)

    Benato, A.; Kærn, Martin Ryhl; Pierobon, Leonardo

    2015-01-01

    This paper is devoted to the investigation of critical dynamic events causing thermochemical decompositionof the working fluid in organic Rankine cycle power systems. The case study is the plant of an oiland gas platform where one of the three gas turbines is combined with an organic Rankine cycl...

  5. Altheim geothermal plant. Power generation by means of an ORC turbogenerator; Geothermieanlagen Altheim. Stromerzeugung mittels Organic-Rankine-Cycle Turbogenerator

    Energy Technology Data Exchange (ETDEWEB)

    Pernecker, G. [Marktgemeindeamt Altheim (Austria)

    1997-12-01

    The report describes the project of the Austrian market town of Altheim to generate electricity by means of an ORC turbogenerator using low-temperature thermal water. The project is to improve the technical and economic situation of the existing industrial-scale geothermal project. (orig.) [Deutsch] Der Bericht beschreibt das Vorhaben der Marktgemeinde Altheim in Oberoesterreich, Strom mittels eines Organic-Rankine-Cycle-Turbogenerators unter Verwendung niedrig temperierten Thermalwassers zu produzieren. Ziel bzw. der Zweck des Projektes ist es, die technische und wirtschaftliche Situation der bestehenden Grossthermieanlage zu verbessern. (orig.)

  6. Design of organic Rankine cycles using a non-conventional optimization approach

    DEFF Research Database (Denmark)

    Andreasen, J. G.; Larsen, Ulrik; Haglind, F.

    2015-01-01

    The organic Rankine cycle is a suitable technology for utilizing low grade heat for electricity production. Compared to the traditional steam Rankine cycle, the organic Rankine cycle is beneficial, since it enables the choice of a working fluid which performs better than steam at low heat input...... temperatures and at lowpower outputs. Selecting the process layout of the organic Rankine cycle and the working fluid are two key design decisions which are critical for the thermodynamic and economic performance of the cycle. The prevailing approach used in the design and optimization of organic Rankine...... product of the overall heat transfer coefficient and the heat transfer area) is assigned to the cycle, while the distribution of this total UA-value to each of the heat exchangers is optimized. Optimizations are carried out for three different marine engine waste heatsources at temperatures ranging from...

  7. Optimal design of compact organic Rankine cycle units for domestic solar applications

    Directory of Open Access Journals (Sweden)

    Barbazza Luca

    2014-01-01

    Full Text Available Organic Rankine cycle turbogenerators are a promising technology to transform the solar radiation harvested by solar collectors into electric power. The present work aims at sizing a small-scale organic Rankine cycle unit by tailoring its design for domestic solar applications. Stringent design criteria, i. e., compactness, high performance and safe operation, are targeted by adopting a multi-objective optimization approach modeled with the genetic algorithm. Design-point thermodynamic variables, e. g., evaporating pressure, the working fluid, minimum allowable temperature differences, and the equipment geometry, are the decision variables. Flat plate heat exchangers with herringbone corrugations are selected as heat transfer equipment for the preheater, the evaporator and the condenser. The results unveil the hyperbolic trend binding the net power output to the heat exchanger compactness. Findings also suggest that the evaporator and condenser minimum allowable temperature differences have the largest impact on the system volume and on the cycle performances. Among the fluids considered, the results indicate that R1234yf and R1234ze are the best working fluid candidates. Using flat plate solar collectors (hot water temperature equal to 75 °C, R1234yf is the optimal solution. The heat exchanger volume ranges between 6.0 and 23.0 dm3, whereas the thermal efficiency is around 4.5%. R1234ze is the best working fluid employing parabolic solar collectors (hot water temperature equal to 120 °C. In such case the thermal efficiency is around 6.9%, and the heat exchanger volume varies from 6.0 to 18.0 dm3.

  8. Organic Rankine Kilowatt Isotope Power System. Final phase I report

    Energy Technology Data Exchange (ETDEWEB)

    1978-07-15

    On 1 August 1975 under Department of Energy Contract EN-77-C-02-4299, Sundstrand Energy Systems commenced development of a Kilowatt Isotope Power System (KIPS) directed toward satisfying the higher power requirements of satellites of the 1980s and beyond. The KIPS is a /sup 238/PuO/sub 2/ fueled organic Rankine cycle turbine power system which will provide design output power in the range of 500 to 2000 W/sub (e)/ with a minimum of system changes. The principal objectives of the Phase 1 development effort were to: conceptually design a flight system; design a Ground Demonstration System (GDS) that is prototypic of the flight system in order to prove the feasibility of the flight system design; fabricate and assemble the GDS; and performance and endurance test the GDS using electric heaters in lieu of the isotope heat source. Results of the work performed under the Phase 1 contract to 1 July 1978 are presented.

  9. Solar-powered Rankine heat pump for heating and cooling

    Science.gov (United States)

    Rousseau, J.

    1978-01-01

    The design, operation and performance of a familyy of solar heating and cooling systems are discussed. The systems feature a reversible heat pump operating with R-11 as the working fluid and using a motor-driven centrifugal compressor. In the cooling mode, solar energy provides the heat source for a Rankine power loop. The system is operational with heat source temperatures ranging from 155 to 220 F; the estimated coefficient of performance is 0.7. In the heating mode, the vapor-cycle heat pump processes solar energy collected at low temperatures (40 to 80 F). The speed of the compressor can be adjusted so that the heat pump capacity matches the load, allowing a seasonal coefficient of performance of about 8 to be attained.

  10. Small-scale health-related indicator acquisition using secondary data spatial interpolation

    Directory of Open Access Journals (Sweden)

    Thompson Mary E

    2010-10-01

    Full Text Available Abstract Background Due to the lack of small-scale neighbourhood-level health related indicators, the analysis of social and spatial determinants of health often encounter difficulties in assessing the interrelations of neighbourhood and health. Although secondary data sources are now becoming increasingly available, they usually cannot be directly utilized for analysis in other than the designed study due to sampling issues. This paper aims to develop data handling and spatial interpolation procedures to obtain small area level variables using the Canadian Community Health Surveys (CCHS data so that meaningful small-scale neighbourhood level health-related indicators can be obtained for community health research and health geographical analysis. Results Through the analysis of spatial autocorrelation, cross validation comparison, and modeled effect comparison with census data, kriging is identified as the most appropriate spatial interpolation method for obtaining predicted values of CCHS variables at unknown locations. Based on the spatial structures of CCHS data, kriging parameters are suggested and potential small-area-level health-related indicators are derived. An empirical study is conducted to demonstrate the effective use of derived neighbourhood variables in spatial statistical modeling. Suggestions are also given on the accuracy, reliability and usage of the obtained small area level indicators, as well as further improvements of the interpolation procedures. Conclusions CCHS variables are moderately spatially autocorrelated, making kriging a valid method for predicting values at unsampled locations. The derived variables are reliable but somewhat smoother, with smaller variations than the real values. As potential neighbourhood exposures in spatial statistical modeling, these variables are more suitable to be used for exploring potential associations than for testing the significance of these associations, especially for associations

  11. FLUOROETHERS AS A WORKING FLUIDS FOR LOW TEMPERATURE ORGANIC RANKINE CYCLE

    Directory of Open Access Journals (Sweden)

    Artemenko S.V

    2014-12-01

    Full Text Available Hydrofluoroethers as a new class of working fluids for the organic Rankine cycle have been considered to utilize the low-potential waste heat. Temperature range 300…400 K was chosen to provide energy conversion of waste heat from fuel cells. The direct assessment of the efficiency criteria for the Rankine cycle via artificial neural networks (ANN was used. To create ANN the critical parameters of substance and normal boiling temperature as input were chosen. The forecast of efficiency criteria for the Rankine cycle as output parameter which reproduces the coefficient of performance with high accuracy and without thermodynamic property calculations was presented.

  12. Analysis of a rotating spool expander for Organic Rankine Cycle applications

    Science.gov (United States)

    Krishna, Abhinav

    Increasing interest in recovering or utilizing low-grade heat for power generation has prompted a search for ways in which the power conversion process may be enhanced. Amongst the conversion systems, the Organic Rankine Cycle (ORC) has generated an enormous amount of interest amongst researchers and system designers. Nevertheless, component level technologies need to be developed and match the range of potential applications. In particular, technical challenges associated with scaling expansion machines (turbines) from utility scale to commercial scale have prevented widespread adoption of the technology. In this regard, this work focuses on a novel rotating spool expansion machine at the heart of an Organic Rankine Cycle. A comprehensive, deterministic simulation model of the rotating spool expander is developed. The comprehensive model includes a detailed geometry model of the spool expander and the suction valve mechanism. Sub-models for mass flow, leakage, heat transfer and friction within the expander are also developed. Apart from providing the ability to characterize the expander in a particular system, the model provides a valuable tool to study the impact of various design variables on the performance of the machine. The investigative approach also involved an experimental program to assess the performance of a working prototype. In general, the experimental data showed that the expander performance was sub-par, largely due to the mismatch of prevailing operating conditions and the expander design criteria. Operating challenges during the shakedown tests and subsequent sub-optimal design changes also detracted from performance. Nevertheless, the results of the experimental program were sufficient for a proof-of-concept assessment of the expander and for model validation over a wide range of operating conditions. The results of the validated model reveal several interesting details concerning the expander design and performance. For example, the match

  13. Large-scale linear system solver using secondary storage: Self-energy in hybrid nanostructures

    Science.gov (United States)

    Badia, J. M.; Movilla, J. L.; Climente, J. I.; Castillo, M.; Marqués, M.; Mayo, R.; Quintana-Ortí, E. S.; Planelles, J.

    2011-02-01

    We present a Fortran library which can be used to solve large-scale dense linear systems, Ax=b. The library is based on the LU decomposition included in the parallel linear algebra library PLAPACK and on its out-of-core extension POOCLAPACK. The library is complemented with a code which calculates the self-polarization charges and self-energy potential of axially symmetric nanostructures, following an induced charge computation method. Illustrative calculations are provided for hybrid semiconductor-quasi-metal zero-dimensional nanostructures. In these systems, the numerical integration of the self-polarization equations requires using a very fine mesh. This translates into very large and dense linear systems, which we solve for ranks up to 3×10. It is shown that the self-energy potential on the semiconductor-metal interface has important effects on the electronic wavefunction. Program summaryProgram title: HDSS (Huge Dense System Solver) Catalogue identifier: AEHU_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEHU_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 98 889 No. of bytes in distributed program, including test data, etc.: 1 009 622 Distribution format: tar.gz Programming language: Fortran 90, C Computer: Parallel architectures: multiprocessors, computer clusters Operating system: Linux/Unix Has the code been vectorized or parallelized?: Yes. 4 processors used in the sample tests; tested from 1 to 288 processors RAM: 2 GB for the sample tests; tested for up to 80 GB Classification: 7.3 External routines: MPI, BLAS, PLAPACK, POOCLAPACK. PLAPACK and POOCLAPACK are included in the distribution file. Nature of problem: Huge scale dense systems of linear equations, Ax=B, beyond standard LAPACK capabilities. Application to calculations of self

  14. Thermodynamic Analysis of a Rankine Cycle Powered Vapor Compression Ice Maker Using Solar Energy

    National Research Council Canada - National Science Library

    Hu, Bing; Bu, Xianbiao; Ma, Weibin

    2014-01-01

      To develop the organic Rankine-vapor compression ice maker driven by solar energy, a thermodynamic model was developed and the effects of generation temperature, condensation temperature, and working...

  15. Thermodynamic analysis of a Rankine cycle powered vapor compression ice maker using solar energy

    National Research Council Canada - National Science Library

    Hu, Bing; Bu, Xianbiao; Ma, Weibin

    2014-01-01

    To develop the organic Rankine-vapor compression ice maker driven by solar energy, a thermodynamic model was developed and the effects of generation temperature, condensation temperature, and working...

  16. Rankin-Selberg methods for closed string amplitudes

    CERN Document Server

    Pioline, Boris

    2014-01-01

    After integrating over supermoduli and vertex operator positions, scattering amplitudes in superstring theory at genus $h\\leq 3$ are reduced to an integral of a Siegel modular function of degree $h$ on a fundamental domain of the Siegel upper half plane. A direct computation is in general unwieldy, but becomes feasible if the integrand can be expressed as a sum over images under a suitable subgroup of the Siegel modular group: if so, the integration domain can be extended to a simpler domain at the expense of keeping a single term in each orbit -- a technique known as the Rankin-Selberg method. Motivated by applications to BPS-saturated amplitudes, Angelantonj, Florakis and I have applied this technique to one-loop modular integrals where the integrand is the product of a Siegel-Narain theta function times a weakly, almost holomorphic modular form. I survey our main results, and take some steps in extending this method to genus greater than one.

  17. Performance analysis of organic Rankine cycles using different working fluids

    Directory of Open Access Journals (Sweden)

    Zhu Qidi

    2015-01-01

    Full Text Available Low-grade heat from renewable or waste energy sources can be effectively recovered to generate power by an organic Rankine cycle (ORC in which the working fluid has an important impact on its performance. The thermodynamic processes of ORCs using different types of organic fluids were analyzed in this paper. The relationships between the ORC’s performance parameters (including evaporation pressure, condensing pressure, outlet temperature of hot fluid, net power, thermal efficiency, exergy efficiency, total cycle irreversible loss, and total heat-recovery efficiency and the critical temperatures of organic fluids were established based on the property of the hot fluid through the evaporator in a specific working condition, and then were verified at varied evaporation temperatures and inlet temperatures of the hot fluid. Here we find that the performance parameters vary monotonically with the critical temperatures of organic fluids. The values of the performance parameters of the ORC using wet fluids are distributed more dispersedly with the critical temperatures, compared with those of using dry/isentropic fluids. The inlet temperature of the hot fluid affects the relative distribution of the exergy efficiency, whereas the evaporation temperature only has an impact on the performance parameters using wet fluid.

  18. Organic Rankine cycle - review and research directions in engine applications

    Science.gov (United States)

    Panesar, Angad

    2017-11-01

    Waste heat to power conversion using Organic Rankine Cycles (ORC) is expected to play an important role in CO2 reductions from diesel engines. Firstly, a review of automotive ORCs is presented focusing on the pure working fluids, thermal architectures and expanders. The discussion includes, but is not limited to: R245fa, ethanol and water as fluids; series, parallel and cascade as architectures; dry saturated, superheated and supercritical as expansion conditions; and scroll, radial turbine and piston as expansion machines. Secondly, research direction in versatile expander and holistic architecture (NOx + CO2) are proposed. Benefits of using the proposed unconventional approaches are quantified using Ricardo Wave and Aspen HYSYS for diesel engine and ORC modelling. Results indicate that, the implementation of versatile piston expander tolerant to two-phase and using cyclopentane can potentially increase the highway drive cycle power by 8%. Furthermore, holistic architecture offering complete utilisation of charge air and exhaust recirculation heat increased the performance noticeably to 5% of engine power at the design point condition.

  19. Biogas Engine Waste Heat Recovery Using Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Alberto Benato

    2017-03-01

    Full Text Available Italy is a leading country in the biogas sector. Energy crops and manure are converted into biogas using anaerobic digestion and, then, into electricity using internal combustion engines (ICEs. Therefore, there is an urgent need for improving the efficiency of these engines taking the real operation into account. To this purpose, in the present work, the organic Rankine cycle (ORC technology is used to recover the waste heat contained in the exhaust gases of a 1 MWel biogas engine. The ICE behavior being affected by the biogas characteristics, the ORC unit is designed, firstly, using the ICE nameplate data and, then, with data measured during a one-year monitoring activity. The optimum fluid and the plant configuration are selected in both cases using an “in-house” optimization tool. The optimization goal is the maximization of the net electric power while the working fluid is selected among 115 pure fluids and their mixtures. Results show that a recuperative ORC designed using real data guarantees a 30% higher net electric power than the one designed with ICE nameplate conditions.

  20. Performance Analysis of Organic Rankine-vapor Compression Ice Maker Utilizing Food Industry Waste Heat

    OpenAIRE

    Bing Hu; Yuanshu Cao; Weibin Ma

    2015-01-01

    To develop the organic Rankine-vapor compression ice maker driven by food industry exhaust gases and engine cooling water, an organic Rankine-vapor compression cycle system was employed for ice making and a thermodynamic model was developed and the effects of working fluid types, hot water temperature and condensation temperature on the system performance were analyzed and the ice making capacity from unit mass hot water and unit power waste heat were evaluated. The calculated results show th...

  1. Waste Heat-to-Power Using Scroll Expander for Organic Rankine Bottoming Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Dieckmann, John [TIAX LLC, Lexington, MA (United States); Smutzer, Chad [TIAX LLC, Lexington, MA (United States); Sinha, Jayanti [TIAX LLC, Lexington, MA (United States)

    2017-05-30

    The objective of this program was to develop a novel, scalable scroll expander for conversion of waste heat to power; this was accomplished and demonstrated in both a bench-scale system as well as a full-scale system. The expander is a key component in Organic Rankine Cycle (ORC) waste heat recovery systems which are used to convert medium-grade waste heat to electric power in a wide range of industries. These types of waste heat recovery systems allow for the capture of energy that would otherwise just be exhausted to the atmosphere. A scroll expander has the benefit over other technologies of having high efficiency over a broad range of operating conditions. The speed range of the TIAX expander (1,200 to 3,600 RPM) enables the shaft power output to directly drive an electric generator and produce 60 Hz electric power without incurring the equipment costs or losses of electronic power conversion. This greatly simplifies integration with the plant electric infrastructure. The TIAX scroll expander will reduce the size, cost, and complexity of a small-scale waste heat recovery system, while increasing the system efficiency compared to the prevailing ORC technologies at similar scale. During this project, TIAX demonstrated the scroll expander in a bench-scale test setup to have isentropic efficiency of 70-75% and operated it successfully for ~200 hours with minimal wear. This same expander was then installed in a complete ORC system driven by a medium grade waste heat source to generate 5-7 kW of electrical power. Due to funding constraints, TIAX was unable to complete this phase of testing, although the initial results were promising and demonstrated the potential of the technology.

  2. Performance Evaluation of a Helical Coil Heat Exchanger Working under Supercritical Conditions in a Solar Organic Rankine Cycle Installation

    Directory of Open Access Journals (Sweden)

    Marija Lazova

    2016-06-01

    Full Text Available Worldwide interest in low grade heat valorization using organic Rankine cycle (ORC technologies has increased significantly. A new small-scale ORC with a net capacity of 3 kW was efficiently integrated with a concentrated solar power technology for electricity generation. The excess heat source from Photovoltaic (PV collectors with a maximum temperature of 100 °C was utilized through a supercritical heat exchanger that uses R-404A as working medium. By ensuring supercritical heat transfer leads to a better thermal match in the heat exchanger and improved overall cycle efficiency. A helical coil heat exchanger was designed by using heat transfer correlations from the literature. These heat transfer correlations were derived for different conditions than ORCs and their estimated uncertainty is ~20%. In order to account for the heat transfer correlation uncertainties this component was oversized by 20%. Next, a prototype was built and installed in an integrated concentrated photovoltaic/thermal (CPV/T/Rankine system. The results from the measurements show that for better estimation of the sizing of the heat exchanger a more accurate correlation is required in order to design an optimal configuration and thus employ cheaper components.

  3. A Co-Powered Biomass and Concentrated Solar Power Rankine Cycle Concept for Small Size Combined Heat and Power Generation

    Directory of Open Access Journals (Sweden)

    Eileen Tortora

    2013-03-01

    Full Text Available The present work investigates the matching of an advanced small scale Combined Heat and Power (CHP Rankine cycle plant with end-user thermal and electric load. The power plant consists of a concentrated solar power field co-powered by a biomass furnace to produce steam in a Rankine cycle, with a CHP configuration. A hotel was selected as the end user due to its high thermal to electric consumption ratio. The power plant design and its operation were modelled and investigated by adopting transient simulations with an hourly distribution. The study of the load matching of the proposed renewable power technology and the final user has been carried out by comparing two different load tracking scenarios, i.e., the thermal and the electric demands. As a result, the power output follows fairly well the given load curves, supplying, on a selected winter day, about 50 GJ/d of thermal energy and the 6 GJ/d of electric energy, with reduced energy dumps when matching the load.

  4. Impact of Microscale and Pilot-Scale Freeze-Drying on Protein Secondary Structures: Sucrose Formulations of Lysozyme and Catalase.

    Science.gov (United States)

    Peters, Björn-Hendrik; Leskinen, Jari T T; Molnár, Ferdinand; Ketolainen, Jarkko

    2015-11-01

    Microscale (MS) freeze-drying offers rapid process cycles for early-stage formulation development. The effects of the MS approach on the secondary structures of two model proteins, lysozyme and catalase, were compared with pilot-scale (PS) vial freeze-drying. The secondary structures were assessed by attenuated total reflection Fourier transformed infrared spectroscopy. Formulations were made with increasing sucrose-protein ratios. Freeze-drying protocols involved regular cooling without thermal treatment and annealing with MS and PS equipment, and cooling rate variations with the MS. Principal component analysis of smoothed second-derivative amide I spectra revealed sucrose-protein ratio-dependent shifts toward α-helical structures. Transferability of sucrose-protein formulations from MS to PS vial freeze-drying was evidenced at regular cooling rates. Local differences in protein secondary structures between the bottom and top of sucrose-catalase samples could be detected at the sucrose-catalase ratios of 1 and 2, this being related to the initial filling height and ice crystal morphology. Annealing revealed temperature, protein, formulation, and sample location-dependent effects influencing surface morphology at the top, or causing protein secondary structure perturbation at the bottom. With the MS approach, protein secondary structure differences at different cooling rates could be detected for sucrose-lysozyme samples at the sucrose-lysozyme ratio of 1. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  5. Preliminary Design and Simulation of a Turbo Expander for Small Rated Power Organic Rankine Cycle (ORC

    Directory of Open Access Journals (Sweden)

    Roberto Capata

    2014-11-01

    Full Text Available Nowadays, the Organic Rankine Cycle (ORC system, which operates with organic fluids, is one of the leading technologies for “waste energy recovery”. It works as a conventional Rankine Cycle but, as mentioned, instead of steam/water, an organic fluid is used. This change allows it to convert low temperature heat into electric energy where required. Large numbers of studies have been carried out to identify the most suitable fluids, system parameters and the various configurations. In the present market, most ORC systems are designed and manufactured for the recovery of thermal energy from various sources operating at “large power rating” (exhaust gas turbines, internal combustion engines, geothermal sources, large melting furnaces, biomass, solar, etc.; from which it is possible to produce a large amount of electric energy (30 kW ÷ 300 kW. Such applications for small nominal power sources, as well as the exhaust gases of internal combustion engines (car sedan or town, ships, etc. or small heat exchangers, are very limited. The few systems that have been designed and built for small scale applications, have, on the other hand, different types of expander (screw, scroll, etc.. These devices are not adapted for placement in small and restricted places like the interior of a conventional car. The aim of this work is to perform the preliminary design of a turbo-expander that meets diverse system requirements such as low pressure, small size and low mass flow rates. The expander must be adaptable to a small ORC system utilizing gas of a diesel engine or small gas turbine as thermal source to produce 2–10 kW of electricity. The temperature and pressure of the exhaust gases, in this case study (400–600 °C and a pressure of 2 bar, imposes a limit on the use of an organic fluid and on the net power that can be produced. In addition to water, fluids such as CO2, R134a and R245fa have been considered. Once the operating fluids has been chosen

  6. Large-scale secondary circulations in the regional climate model COSMO-CLM

    OpenAIRE

    Becker, Nico

    2016-01-01

    Regional climate models (RCMs) are used to add smaller scales to coarser resolved driving data, e. g. from global climate models (GCMs), by using a higher resolution on a limited domain. However, RCMs do not only add scales which are not resolved by the driving model but also deviate from the driving data on larger scales. Thus, RCMs are able to improve the large scales prescribed by the driving data. However, large scale deviations can also lead to instabilities at the model boundaries. A sy...

  7. Observation of a Large-scale Quasi-circular Secondary Ribbon Associated with Successive Flares and a Halo CME

    Science.gov (United States)

    Lim, Eun-Kyung; Yurchyshyn, Vasyl; Kumar, Pankaj; Cho, Kyuhyoun; Jiang, Chaowei; Kim, Sujin; Yang, Heesu; Chae, Jongchul; Cho, Kyung-Suk; Lee, Jeongwoo

    2017-12-01

    Solar flare ribbons provide an important clue to the magnetic reconnection process and associated magnetic field topology in the solar corona. We detected a large-scale secondary flare ribbon of a circular shape that developed in association with two successive M-class flares and one coronal mass ejection. The ribbon revealed interesting properties such as (1) a quasi-circular shape and enclosing the central active region (AR); (2) the size as large as 500″ by 650″ (3) successive brightenings in the clockwise direction at a speed of 160 km s-1 starting from the nearest position to the flaring sunspots; (4) radial contraction and expansion in the northern and the southern part, respectively, at speeds of ≤10 km s-1. Using multi-wavelength data from Solar Dynamics Observatory, RHESSI, XRT, and Nobeyama, along with magnetic field extrapolations, we found that: (1) the secondary ribbon location is consistent with those of the field line footpoints of a fan-shaped magnetic structure that connects the flaring region and the ambient decaying field; (2) the second M2.6 flare occurred when the expanding coronal loops driven by the first M2.0 flare encountered the background decayed field; (3) immediately after the second flare, the secondary ribbon developed along with dimming regions. Based on our findings, we suggest that interaction between the expanding sigmoid field and the overlying fan-shaped field triggered the secondary reconnection that resulted in the field opening and formation of the quasi-circular secondary ribbon. We thus conclude that interaction between the AR and the ambient large-scale fields should be taken into account to fully understand the entire eruption process.

  8. Teachers' Attitude towards ICT Use in Secondary Schools: A Scale Development Study

    Science.gov (United States)

    Aydin, Mehmet Kemal; Semerci, Ali; Gürol, Mehmet

    2016-01-01

    The current study aims to develop a valid and reliable instrument that measures secondary school teachers' attitudes towards ICT use in teaching and learning process. A cross-sectional survey design was employed with a group of 173 teachers. Based on the literature review, a pool of 21 items was proposed and reviewed by a board of experts. As to…

  9. EMISSIONS OF TRACE PRODUCTS OF INCOMPLETE COMBUSTION FROM A PILOT-SCALE INCINERATOR SECONDARY COMBUSTION CHAMBER

    Science.gov (United States)

    Experiments were performed on a 73 kW rotary kiln incinerator simulator equipped with a 73 kW secondary combustion chamber (SCC) to examine emissions of products of incomplete combustion (PICs) resulting from incineration of carbon tetrachloride (CCl4) and dichlorometh...

  10. The LA aggression scale for elementary school and upper secondary school students: Examination of psychometric properties of a new multidimensional measure of self- reported aggression

    OpenAIRE

    Kozina Ana

    2013-01-01

    The paper introduces a new multidimensional scale LA (lestvica agresivnosti [Aggression Scale]) for measuring self-reported aggression in elementary and upper secondary school students in Slovenia. The scale has been developed with a special focus on the school setting, using three elementary school samples (preliminary study: N=2777; main study: N=10427 and validity and test-retest study: N=191) representative of 4th and 8th grade students in Slovenia and one upper secondary school sam...

  11. Reliability and validity of the Student Perceptions of School Cohesion Scale in a sample of Salvadoran secondary school students

    Directory of Open Access Journals (Sweden)

    Arrivillaga Marcela

    2009-11-01

    Full Text Available Abstract Background Despite a growing body of research from the United States and other industrialized countries on the inverse association between supportive social relationships in the school and youth risk behavior engagement, research on the measurement of supportive school social relationships in Central America is limited. We examined the psychometric properties of the Student Perceptions of School Cohesion (SPSC scale, a 10-item scale that asks students to rate with a 5-point Likert-type response scale their perceptions of the school social environment, in a sample of public secondary school students (mean age = 15 years living in central El Salvador. Methods Students (n = 982 completed a self-administered questionnaire that included the SPSC scale along with measures of youth health risk behaviors based on the Center for Disease Control and Prevention's Youth Risk Behavior Survey. Exploratory factor analysis was used to assess the factor structure of the scale, and two internal consistency estimates of reliability were computed. Construct validity was assessed by examining whether students who reported low school cohesion were significantly more likely to report physical fighting and illicit drug use. Results Results indicated that the SPSC scale has three latent factors, which explained 61.6% of the variance: supportive school relationships, student-school connectedness, and student-teacher connectedness. The full scale and three subscales had good internal consistency (rs = .87 and α = .84 for the full scale; rs and α between .71 and .75 for the three subscales. Significant associations were found between the full scale and all three subscales with physical fighting (p ≤ .001 and illicit drug use (p Conclusion Findings provide evidence of reliability and validity of the SPSC for the measurement of supportive school relationships in Latino adolescents living in El Salvador. These findings provide a foundation for further research on

  12. Application of Biomass from Palm Oil Mill for Organic Rankine Cycle to Generate Power in North Sumatera Indonesia

    Science.gov (United States)

    Nur, T. B.; Pane, Z.; Amin, M. N.

    2017-03-01

    Due to increasing oil and gas demand with the depletion of fossil resources in the current situation make efficient energy systems and alternative energy conversion processes are urgently needed. With the great potential of resources in Indonesia, make biomass has been considered as one of major potential fuel and renewable resource for the near future. In this paper, the potential of palm oil mill waste as a bioenergy source has been investigated. An organic Rankine cycle (ORC) small scale power plant has been preliminary designed to generate electricity. The working fluid candidates for the ORC plant based on the heat source temperature domains have been investigated. The ORC system with a regenerator has higher thermal efficiency than the basic ORC system. The study demonstrates the technical feasibility of ORC solutions in terms of resources optimizations and reducing of greenhouse gas emissions.

  13. Improving the efficiency of heat supply systems on the basis of plants operating on organic Rankine cycle

    Science.gov (United States)

    Solomin, I. N.; Daminov, A. Z.; Sadykov, R. A.

    2017-11-01

    Results of experimental and analytical studies of the plant main element – plant turbomachine (turbo-expander) operating on organic Rankine cycle were obtained for facilities of the heat supply systems of small-scale power generation. At simultaneous mathematical modeling and experimental studies it was found that the best working medium to be used in the turbomachines of these plants is Freon R245fa which has the most suitable calorimetric properties to be used in the cycle. The mathematical model of gas flow in the turbomachine was developed. The main engineering dependencies to calculate the optimal design parameters of the turbomachine were obtained. The engineering problems of providing the minimum axial size of the turbomachine impeller were solved and the main design elements were unified.

  14. Anticipatory Traumatic Reaction: Outcomes Arising From Secondary Exposure to Disasters and Large-Scale Threats.

    Science.gov (United States)

    Hopwood, Tanya L; Schutte, Nicola S; Loi, Natasha M

    2017-09-01

    Two studies, with a total of 707 participants, developed and examined the reliability and validity of a measure for anticipatory traumatic reaction (ATR), a novel construct describing a form of distress that may occur in response to threat-related media reports and discussions. Exploratory and confirmatory factor analysis resulted in a scale comprising three subscales: feelings related to future threat; preparatory thoughts and actions; and disruption to daily activities. Internal consistency was .93 for the overall ATR scale. The ATR scale demonstrated convergent validity through associations with negative affect, depression, anxiety, stress, neuroticism, and repetitive negative thinking. The scale showed discriminant validity in relationships to Big Five characteristics. The ATR scale had some overlap with a measure of posttraumatic stress disorder, but also showed substantial separate variance. This research provides preliminary evidence for the novel construct of ATR as well as a measure of the construct. The ATR scale will allow researchers to further investigate anticipatory traumatic reaction in the fields of trauma, clinical practice, and social psychology.

  15. Optimization of organic Rankine cycle power systems considering multistage axial turbine design

    DEFF Research Database (Denmark)

    Meroni, Andrea; Andreasen, Jesper Graa; Persico, Giacomo

    2018-01-01

    Organic Rankine cycle power systems represent a viable and efficient solution for the exploitation of medium-to-low temperature heat sources. Despite the large number of commissioned units, there is limited literature on the design and optimization of organic Rankine cycle power systems considering......-butane yields the best compromise in terms of cycle net power output, turbine cost and efficiency for the considered case study. When a conservative design approach is adopted, the turbine features a two-stage configuration with supersonic converging nozzles and post-expansion. Conversely, a single...... multistage turbine design. This work presents a preliminary design methodology and working fluid selection for organic Rankine cycle units featuring multistage axial turbines. The method is then applied to the case of waste heat recovery from a large marine diesel engine. A multistage axial turbine model...

  16. Optimization of organic Rankine cycle power systems considering multistage axial turbine design

    DEFF Research Database (Denmark)

    Meroni, Andrea; Andreasen, Jesper Graa; Persico, Giacomo

    2017-01-01

    Organic Rankine cycle power systems represent a viable and efficient solution for the exploitation of medium-to-low temperature heat sources. Despite the large number of commissioned units, there is limited literature on the design and optimization of organic Rankine cycle power systems considering......-butane yields the best compromise in terms of cycle net power output, turbine cost and efficiency for the considered case study. When a conservative design approach is adopted, the turbine features a two-stage configuration with supersonic converging nozzles and post-expansion. Conversely, a single...... multistage turbine design. This work presents a preliminary design methodology and working fluid selection for organic Rankine cycle units featuring multistage axial turbines. The method is then applied to the case of waste heat recovery from a large marine diesel engine. A multistage axial turbine model...

  17. Thermodynamic analysis of a Rankine cycle powered vapor compression ice maker using solar energy.

    Science.gov (United States)

    Hu, Bing; Bu, Xianbiao; Ma, Weibin

    2014-01-01

    To develop the organic Rankine-vapor compression ice maker driven by solar energy, a thermodynamic model was developed and the effects of generation temperature, condensation temperature, and working fluid types on the system performance were analyzed. The results show that the cooling power per square meter collector and ice production per square meter collector per day depend largely on generation temperature and condensation temperature and they increase firstly and then decrease with increasing generation temperature. For every working fluid there is an optimal generation temperature at which organic Rankine efficiency achieves the maximum value. The cooling power per square meter collector and ice production per square meter collector per day are, respectively, 126.44 W m(-2) and 7.61 kg m(-2) day(-1) at the generation temperature of 140 °C for working fluid of R245fa, which demonstrates the feasibility of organic Rankine cycle powered vapor compression ice maker.

  18. Combined Turbine and Cycle Optimization for Organic Rankine Cycle Power Systems—Part B

    DEFF Research Database (Denmark)

    La Seta, Angelo; Meroni, Andrea; Andreasen, Jesper Graa

    2016-01-01

    due to the peculiar physical properties of the working fluid and the gas-dynamic phenomena occurring in the machine. Unlike steam Rankine and Brayton engines, organic Rankine cycle expanders combine small enthalpy drops with large expansion ratios. These features yield turbine designs with few highly-loaded...... variables affecting the turbine design. Part B of this two-part paper presents the first application of a design method where the thermodynamic cycle optimization is combined with calculations of the maximum expander performance using the mean-line design tool described in part A. The high computational...

  19. Development of Want-Need Perception Scale for Primary and Secondary School Students

    Science.gov (United States)

    Bakirtas, Hülya; Tonga, Deniz

    2016-01-01

    In the development of the national economies, the economy education in school curricula has an important place, because students may not have received the necessary economic realities and requirements. For that reason, it is necessary to determine the perception of wants and needs of children. In this study, it was aimed to develop a scale for…

  20. Part-Load Performance of a Wet Indirectly Fired Gas Turbine Integrated with an Organic Rankine Cycle Turbogenerator

    DEFF Research Database (Denmark)

    Pierobon, Leonardo; Nguyen, Tuong-Van; Mazzucco, Andrea

    2014-01-01

    ) fueled by woodchips and an organic Rankine cycle (ORC) turbogenerator. An exergy analysis is performed to identify the sources of inefficiencies, the optimal design variables, and the most suitable working fluid for the organic Rankine process. This step enables to parametrize the part-load model...

  1. Time-resolved analysis of primary volatile emissions and secondary aerosol formation potential from a small-scale pellet boiler

    Science.gov (United States)

    Czech, Hendryk; Pieber, Simone M.; Tiitta, Petri; Sippula, Olli; Kortelainen, Miika; Lamberg, Heikki; Grigonyte, Julija; Streibel, Thorsten; Prévôt, André S. H.; Jokiniemi, Jorma; Zimmermann, Ralf

    2017-06-01

    Small-scale pellet boilers and stoves became popular as a wood combustion appliance for domestic heating in Europe, North America and Asia due to economic and environmental aspects. Therefore, an increasing contribution of pellet boilers to air pollution is expected despite their general high combustion efficiency. As emissions of primary organic aerosol (POA) and permanent gases of pellet boilers are well investigated, the scope of this study was to investigate the volatile organic emissions and the formation potential of secondary aerosols for this type of appliance. Fresh and aged emissions were analysed by a soot-particle aerosol time-of-flight mass spectrometry (SP-AMS) and the molecular composition of the volatile precursors with single-photon ionisation time-of-flight mass spectrometry (SPI-TOFMS) at different pellet boiler operation conditions. Organic emissions in the gas phase were dominated by unsaturated hydrocarbons while wood-specific VOCs, e.g. phenolic species or substituted furans, were only detected during the starting phase. Furthermore, organic emissions in the gas phase were found to correlate with fuel grade and combustion technology in terms of secondary air supply. Secondary organic aerosols of optimised pellet boiler conditions (OPT, state-of-the-art combustion appliance) and reduced secondary air supply (RSA, used as a proxy for pellet boilers of older type) were studied by simulating atmospheric ageing in a Potential Aerosol Mass (PAM) flow reactor. Different increases in OA mass (55% for OPT, 102% for RSA), associated with higher average carbon oxidation state and O:C, could be observed in a PAM chamber experiment. Finally, it was found that derived SOA yields and emission factors were distinctly lower than reported for log wood stoves.

  2. Development and Validation of the ADAS Scale and Prediction of Attitudes Toward Affective-Sexual Diversity Among Spanish Secondary Students.

    Science.gov (United States)

    Garrido-Hernansaiz, Helena; Martín-Fernández, Manuel; Castaño-Torrijos, Aida; Cuevas, Isabel

    2017-08-25

    Violence against non-heterosexual adolescents in educational contexts remains a worrying reality, but no adequate attitudes toward affective-sexual diversity (AtASD) measure exists for Spanish adolescent students. We developed a 27-item scale including cognitive, affective, and behavioral aspects, which was completed by 696 secondary school students from the Madrid area. Factor analyses suggested a unidimensional model, Cronbach's alpha indicated excellent scale scores reliability, and item calibration under the item response theory framework showed that the scale is especially informative for homophobic attitudes. A hierarchical multiple regression analysis showed that variables traditionally related to AtASD (gender, age, religion, nationality, perceived parental/peer attitudes, direct contact with LGB people) also were so in our sample. Moreover, interest in sexuality topics and perceived center's efforts to provide AtASD education were related to better AtASD. Our scale was reliable and valid, and it may also prove useful in efforts to detect those students with homophobic attitudes and to guide interventions.

  3. A Comparison of Organic and Steam Rankine Cycle Power Systems for Waste Heat Recovery on Large Ships

    DEFF Research Database (Denmark)

    Andreasen, Jesper Graa; Meroni, Andrea; Haglind, Fredrik

    2017-01-01

    %) fuel case. The processes were compared based on their off-design performance for diesel engine loads in the range between 25% and 100%. The fluids considered in the organic Rankine cycle process were MM(hexamethyldisiloxane), toluene, n-pentane, i-pentane and c-pentane. The results of the comparison...... indicate that the net power output of the steam Rankine cycle process is higher at high engine loads, while the performance of the organic Rankine cycle units is higher at lower loads. Preliminary turbine design considerations suggest that higher turbine efficiencies can be obtained for the ORC unit......This paper presents a comparison of the conventional dual pressure steam Rankine cycle process and the organic Rankine cycle process for marine engine waste heat recovery. The comparison was based on a container vessel, and results are presented for a high-sulfur (3 wt %) and low-sulfur (0.5 wt...

  4. Final Report. Conversion of Low Temperature Waste Heat Utilizing Hermetic Organic Rankine Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Fuller, Robert L.

    2005-04-20

    The design of waste heat recovery using the organic Rankine cycle (ORC) engine is updated. Advances in power electronics with lower cost enable the use of a single shaft, high-speed generator eliminating wear items and allowing hermetic sealing of the working fluid. This allows maintenance free operation and a compact configuration that lowers cost, enabling new market opportunities.

  5. Method of optimizing performance of Rankine cycle power plants. [US DOE Patent

    Science.gov (United States)

    Pope, W.L.; Pines, H.S.; Doyle, P.A.; Silvester, L.F.

    1980-06-23

    A method is described for efficiently operating a Rankine cycle power plant to maximize fuel utilization efficiency or energy conversion efficiency or minimize costs by selecting a turbine fluid inlet state which is substantially on the area adjacent and including the transposed critical temperature line.

  6. Theoretical and experimental research of organic Rankine cycle steam turbine plants

    Science.gov (United States)

    Kishkin, A. A.; Delkov, A. V.; Melkozerov, M. G.

    2017-10-01

    Currently steam power cycles using organic actuation fluid - Freon, ammonia, ethanol, isobutene, etc are becoming increasingly important. Such cycles are called Organic Rankine Cycle (ORC). With the help of such cycles it is possible to use low-grade heat sources in the production of mechanical and electrical energy.

  7. A Comparison of Organic and Steam Rankine Cycle Power Systems for Waste Heat Recovery on Large Ships

    Directory of Open Access Journals (Sweden)

    Jesper Graa Andreasen

    2017-04-01

    Full Text Available This paper presents a comparison of the conventional dual pressure steam Rankine cycle process and the organic Rankine cycle process for marine engine waste heat recovery. The comparison was based on a container vessel, and results are presented for a high-sulfur (3 wt % and low-sulfur (0.5 wt % fuel case. The processes were compared based on their off-design performance for diesel engine loads in the range between 25% and 100%. The fluids considered in the organic Rankine cycle process were MM(hexamethyldisiloxane, toluene, n-pentane, i-pentane and c-pentane. The results of the comparison indicate that the net power output of the steam Rankine cycle process is higher at high engine loads, while the performance of the organic Rankine cycle units is higher at lower loads. Preliminary turbine design considerations suggest that higher turbine efficiencies can be obtained for the ORC unit turbines compared to the steam turbines. When the efficiency of the c-pentane turbine was allowed to be 10% points larger than the steam turbine efficiency, the organic Rankine cycle unit reaches higher net power outputs than the steam Rankine cycle unit at all engine loads for the low-sulfur fuel case. The net power production from the waste heat recovery units is generally higher for the low-sulfur fuel case. The steam Rankine cycle unit produces 18% more power at design compared to the high-sulfur fuel case, while the organic Rankine cycle unit using MM produces 33% more power.

  8. Pilot-scale investigation on the removal of organic foulants in secondary effluent by slow sand filtration prior to ultrafiltration.

    Science.gov (United States)

    Zheng, Xing; Ernst, Mathias; Jekel, Martin

    2010-05-01

    Natural biofiltration processes have been verified as effective pre-treatment choice improving the performance of low-pressure membranes (MF/UF) in wastewater reclamation. In the present work, pilot-scale slow sand filtration (SSF) was used to simulate bank filtration at high filtration rates (from 0.25m/h to 0.5m/h) to filter secondary effluent prior to UF. The results showed that SSF improved the performance of UF to a large extent. Related to previous work biopolymers are considered as major dissolved organic foulants in treated wastewater. The removal of these organic foulants in slow sand filters and factors affecting the performance of SSF were investigated. It was observed that the removal of biopolymers took place mainly at the upper sand layer and was related to biological degradation. Tests on the degradability of biopolymers verified that they are biodegradable. Sixteen months monitoring of biopolymer concentration in the secondary effluent indicated that it varied seasonally. In winter season the concentration was much higher than during the summer months. Higher temperature and lower biopolymer concentration led to more effective foulants removal and more sustainable operation of SSF. During the whole experimental period, the performance of SSF was always better at filtration rate of 0.25m/h than at 0.5m/h. Under the present experimental conditions, SSF exhibited stable and effective biopolymer removal at temperatures higher than 15 degrees C, at biopolymer concentrations lower than 0.5mg C/L and with sufficient oxygen available.

  9. Multi-Objective Optimization of Organic Rankine Cycle Power Plants Using Pure and Mixed Working Fluids

    DEFF Research Database (Denmark)

    Andreasen, Jesper Graa; Kærn, Martin Ryhl; Pierobon, Leonardo

    2016-01-01

    For zeotropic mixtures, the temperature varies during phase change, which is opposed to the isothermal phase change of pure fluids. The use of such mixtures as working fluids in organic Rankine cycle power plants enables a minimization of the mean temperature difference of the heat exchangers......, which is beneficial for cycle performance. On the other hand, larger heat transfer surface areas are typically required for evaporation and condensation when zeotropic mixtures are used as working fluids. In order to assess the feasibility of using zeotropic mixtures, it is, therefore, important...... to consider the additional costs of the heat exchangers. In this study, we aim at evaluating the economic feasibility of zeotropic mixtures compared to pure fluids. We carry out a multi-objective optimization of the net power output and the component costs for organic Rankine cycle power plants using low...

  10. Prospects of the use of nanofluids as working fluids for organic Rankine cycle power systems

    DEFF Research Database (Denmark)

    Mondejar, Maria E.; Andreasen, Jesper G.; Regidor, Maria

    2017-01-01

    The search of novel working fluids for organic Rankine cycle power systems is driven by the recent regulations imposing additional phase-out schedules for substances with adverse environmental characteristics. Recently, nanofluids (i.e. colloidal suspensions of nanoparticles in fluids) have been...... suggested as potential working fluids for organic Rankine cycle power systems due to their enhanced thermal properties, potentially giving advantages with respect to the design of the components and the cycle performance. Nevertheless, a number of challenges concerning the use of nanofluids must...... be investigated prior to their practical use. Among other things, the trade-off between enhanced heat transfer and increased pressure drop in heat exchangers, and the impact of the nanoparticles on the working fluid thermophysical properties, must be carefully analyzed. This paper is aimed at evaluating...

  11. Equation of State Selection for Organic Rankine Cycle Modeling Under Uncertainty

    DEFF Research Database (Denmark)

    Frutiger, Jerome; O'Connell, John; Abildskov, Jens

    combustion, geothermal and solar heat sources. The working fluid is essential to the performance of the cycle. In order to evaluate and test promising fluid candidates, an appropriate Equation of State (EoS) [1] is necessary. For ORC applications, an EoS is commonly selected based on goodness-of-fits to data......In recent years there has been a great interest in the design and selection of working fluids for low-temperature Organic Rankine Cycles (ORC), to efficiently produce electrical power from waste heat from chemical engineering applications, as well as from renewable energy sources such as biomass...... cycle, all influence the model output uncertainty. The procedure is highlighted for an ORC for with a low-temperature heat source from exhaust gas from a marine diesel engine.[1] Saleh B, Koglbauer G, Wendland M, Fischer J. Working fluids for lowtemperature organic Rankine cycles. Energy 2007...

  12. Economic analysis of a dish-Rankine solar thermal power system

    Science.gov (United States)

    Pons, R. L.; Irwin, R. E.

    An analysis of the performance and costs of a first generation dish Rankine solar thermal power system for small community and industrial applications is presented. The system is of the point-focusing distributed receiver type, with distributed generation and employs multiple paraboloidal concentrators with organic Rankine cycle power conversion systems at the focus of each dish. Projected life cycle energy costs for a fully developed and mass produced system are shown to be competitive with costs projected in the near future for electricity generated by more conventional means. It is shown that: (1) the method of rating plant poer output has a minor influence on life cycle energy cost, (2) optimum dish size is greater than 12m, (3) energy cost is virtually independent of plant size above 1 MW sub e and (4) dish spacing and geometric arrangement can be optimized to reduce energy cost.

  13. Experimental Study of a Low-Temperature Power Generation System in an Organic Rankine Cycle

    DEFF Research Database (Denmark)

    Mu, Yongchao; Zhang, Yufeng; Deng, Na

    2015-01-01

    as the engine of the power generator. The style of the preheater was a shell and tube heat exchanger, which could provide a long path for the working fluid. A flooded heat exchanger with a high heat transfer coefficient was taken as the evaporator. R134a was used as working fluid for the Rankine cycle......This paper presents a new power generation system under the principle of organic Rankine cycle which can generate power with a low-temperature heat source. A prototype was built to investigate the proposed system. In the prototype, an air screw compressor was converted into an expander and used...... in the system. This study compared and analyzed the experimental performance of the prototype at different heat source temperatures. The results show that the preheater and flooded evaporator was used for sensible heating and latent heating of the working fluid, respectively, as expected. When the temperature...

  14. Combined Turbine and Cycle Optimization for Organic Rankine Cycle Power Systems—Part A

    DEFF Research Database (Denmark)

    Meroni, Andrea; La Seta, Angelo; Andreasen, Jesper Graa

    2016-01-01

    Rankine cycle power systems. In this two-part paper, an overall cycle model and a model of an axial turbine were combined in order to provide a comprehensive preliminary design of the organic Rankine cycle unit, taking into account both cycle and turbine optimal designs. Part A presents the preliminary......Axial-flow turbines represent a well-established technology for a wide variety of power generation systems. Compactness, flexibility, reliability and high efficiency have been key factors for the extensive use of axial turbines in conventional power plants and, in the last decades, in organic...... turbine design model, the details of the validation and a sensitivity analysis on the main parameters, in order to minimize the number of decision variables in the subsequent turbine design optimization. Part B analyzes the application of the combined turbine and cycle designs on a selected case study...

  15. Study of toluene stability for an Organic Rankine Cycle (ORC) space-based power system

    Science.gov (United States)

    Havens, Vance; Ragaller, Dana

    1988-01-01

    The design, fabrication, assembly, and endurance operation of a dynamic test loop, built to evaluate the thermal stability of a proposed Organic Rankine Cycle (ORC) working fluid, is discussed. The test fluid, toluene, was circulated through a heater, simulated turbine, regenerator, condenser and pump to duplicate an actual ORC system. The maximum nominal fluid temperature, 750 F, was at the turbine simulator inlet. Samples of noncondensible gases and liquid toluene were taken periodically during the test. The samples were analyzed to identify the degradation products formed and the quantity of these products. From these data it was possible to determine the degradation rate of the working fluid and the generation rate of noncondensible gases. A further goal of this work was to relate the degradation observed in the dynamic operating loop to degradation obtained in isothermal capsule tests. This relationship was the basis for estimating the power loop degradation in the Space Station Organic Rankine Cycle system.

  16. Application of unscented Kalman filter for condition monitoring of an organic Rankine cycle turbogenerator

    DEFF Research Database (Denmark)

    Pierobon, Leonardo; Schlanbusch, Rune; Kandepu, Rambabu

    2014-01-01

    emphasis on compactness and reliability. In such context, organic Rankine cycle turbogenerators are a promising technology. The implementation of an organic Rankine cycle unit is thus considered for the power system of the Draugen offshore platform in the northern sea, which is the case study......This work relates to a project focusing on energy optimization on offshore facilities. On oil and gas platforms it is common practice to employ gas turbines for power production. So as to increase the system performance and reduce emissions, a bottoming cycle unit can be designed with particular...... for this project. Considering the plant dynamics, it is of paramount importance to monitor the peak temperatures within the once-through boiler serving the bottoming unit to prevent the decomposition of the working fluid. This paper accordingly aims at applying the unscented Kalman filter to estimate...

  17. Effects of local-scale decontamination in a secondary forest contaminated after the Fukushima nuclear power plant accident.

    Science.gov (United States)

    Ayabe, Yoshiko; Hijii, Naoki; Takenaka, Chisato

    2017-09-01

    We investigated whether local-scale decontamination (removal of the litter layer, superficial soil layer, and understory) in a secondary forest contaminated by the Fukushima nuclear power plant accident reduced 137 Cs contamination of the soil and litter. We also measured 137 Cs concentrations in plants and in the web-building spider Nephila clavata (Nephilidae: Arachnida), as an indicator species, to examine 137 Cs contamination in arthropods. One month after decontamination, the total 137 Cs contamination (soil + litter) was reduced by 20% (100 kBq·m -2 ) relative to that in an adjacent untreated (i.e., contaminated) area, which was however not statistically significant. Four months after decontamination, 137 Cs in the decontaminated area had increased to a level similar to those in the untreated area, and the air radiation dose in the decontaminated area was about 2.1 μSv·h -1 , significantly higher than that in the untreated area (1.9 μSv·h -1 ). This may have been attributed to a torrential rain event. Although no statistically significant reduction was observed, most spiders had a lower 137 Cs contamination than that before the decontamination. This implied that the decontamination may have reduced 137 Cs transfer from soil via litter to N. clavata through the detrital food chains, but may not have reduced the amount of 137 Cs transfer through grazing food chains because the concentration of 137 Cs in living tree leaves was not reduced by the decontamination. In autumn, about 2 kBq·m -2 of 137 Cs was supplied from foliage to the ground by litterfall. The results suggested that removal of the litter and superficial soil layers in a contaminated forest may be ineffective. The present study suggests that the local-scale decontamination in a secondary forest had no effect on the reduction of 137 Cs contamination in the treated area. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Investigations on the application of zeotropic fluid mixtures in the organic rankine cycle for the geothermal power generation; Untersuchung zum Einsatz von zeotropen Fluidgemischen im Organic Rankine Cycle fuer die geothermische Stromerzeugung

    Energy Technology Data Exchange (ETDEWEB)

    Heberle, Florian

    2013-04-01

    The organic rankine cycle is a thermodynamic cycle process which uses an organic fluid working fluid instead of water in comparison to the commercial rankine process. The organic rankine cycle facilitates sufficiently high pressures at moderate temperatures. The organic rankine cycle significantly expands the technically possible and economically feasible ranges of application of such heat and power processes. The geothermal power is a very attractive field of application. Thermal water with a temperature of nearly 100 Celsius can be used for the power generation by means of the organic rankine cycle. Especially zeotropic mixtures are interesting as a working fluid. This is due to a non-isothermal phase change to a temperature glide which adapts very well to the temperature progress of the heat source. The author of the book under consideration reports on the application of different mixtures in the organic rankine cycle. The evaluation is based on a thermodynamic analysis and considers also toxicological, ecologic, technical as well as economic aspects.

  19. Working fluid selection for the Organic Rankine Cycle (ORC) exhaust heat recovery of an internal combustion engine power plant

    Science.gov (United States)

    Douvartzides, S.; Karmalis, I.

    2016-11-01

    Organic Rankine cycle technology is capable to efficiently convert low-grade heat into useful mechanical power. In the present investigation such a cycle is used for the recovery of heat from the exhaust gases of a four stroke V18 MAN 51/60DF internal combustion engine power plant operating with natural gas. Design is focused on the selection of the appropriate working fluid of the Rankine cycle in terms of thermodynamic, environmental and safety criteria. 37 candidate fluids have been considered and all Rankine cycles examined were subcritical. The thermodynamic analysis of all fluids has been comparatively undertaken and the effect of key operation conditions such as the evaporation pressure and the superheating temperature was taken into account. By appropriately selecting the working fluid and the Rankine cycle operation conditions the overall plant efficiency was improved by 5.52% and fuel consumption was reduced by 12.69%.

  20. System and method for regulating EGR cooling using a Rankine cycle

    Energy Technology Data Exchange (ETDEWEB)

    Ernst, Timothy C.; Morris, Dave

    2017-08-29

    This disclosure relates to a waste heat recovery (WHR) system and method for regulating exhaust gas recirculation (EGR) cooling, and more particularly, to a Rankine cycle WHR system and method, including a recuperator bypass arrangement to regulate EGR exhaust gas cooling for engine efficiency improvement and thermal management. This disclosure describes other unique bypass arrangements for increased flexibility in the ability to regulate EGR exhaust gas cooling.

  1. Exergetic Analysis of an Integrated Tri-Generation Organic Rankine Cycle

    OpenAIRE

    Ratha Z. Mathkor; Brian Agnew; Mohammed A. Al-Weshahi; Fathi Latrsh

    2015-01-01

    This paper reports on a study of the modelling, validation and analysis of an integrated 1 MW (electrical output) tri-generation system energized by solar energy. The impact of local climatic conditions in the Mediterranean region on the system performance was considered. The output of the system that comprised a parabolic trough collector (PTC), an organic Rankine cycle (ORC), single-effect desalination (SED), and single effect LiBr-H2O absorption chiller (ACH) was electrical power, distille...

  2. Comparison of Organic Rankine Cycle Under Varying Conditions Using Turbine and Twin-Screw Expanders

    OpenAIRE

    Read, M G; Smith, I.K.; Stosic, N.

    2015-01-01

    A multi-variable optimization program has been developed to investigate the performance of Organic Rankine Cycles (ORCs) for low temperature heat recovery applications. This cycle model contains detailed thermodynamic models of the system components, and the methods used to match the operation of the expander to the requirements of the cycle are described. Two types of ORC system are considered; one containing a turbine to expand dry saturated or superheated vapour, and one with a twin-screw ...

  3. Comparison of organic rankine cycle systems under varying conditions using turbine and twin-screw expanders

    OpenAIRE

    Read, M G; Smith, I.K.; Stosic, N.; Kovacevic, A.

    2016-01-01

    A multi-variable optimization program has been developed to investigate the performance of Organic Rankine Cycles (ORCs) for low temperature heat recovery applications using both turbine and twin-screw expanders when account is taken of performance variation due to changes in ambient conditions. The cycle simulation contains thermodynamic models of both types of expander. In the case of the twin-screw machine, the methods used to match the operation of the expander to the requirements of the ...

  4. Autonomous low-temperature solar Rankine cycle system for reverse osmosis desalination

    Energy Technology Data Exchange (ETDEWEB)

    Manolakos, D.; Makris, G.; Papadakis, G.; Kyritsis, S. [Agricultural University of Athens (Greece). Dept. of Agricultural Engineering; Bouzianas, K. [Hellas Energy K. Bouzianas P. Moschovitis and Co., Athens (Greece)

    2004-07-01

    The research regards the development, application testing and performance evaluation of a low temperature solar organic Rankine cycle system for Reverse Osmosis (RO) desalination. Below is given a technical description of the system under development: Thermal energy produced by the solar array evaporates the working fluid (HFC- 134a) in the evaporator surface. The super-heated vapour is driven to the expanders where the generated mechanical work produced by the Rankine cycle drives the RO unit pumps (high pressure pump, cooling water pump, feed water pump) and circulating pump. The saturated vapour at the expanders' outlet is directed to the condenser and condensates. On the condenser surface, seawater is pre-heated and directed to the seawater reservoir. Seawater pre-heating is applied to increase the fresh water recovery ratio. The seawater tank is insulated. The use of seawater on the condenser surface decreases the temperature of ''Low Temperature Reservoir'' of Rankine cycle thus a better cycle efficiency is achieved. For the prototype system 240 m2 of vacuum tube solar collectors will be deployed. The evaporator and condenser capacity is estimated to be about 100 kW. For these systems' characteristics and considering a water recovery ratio of seawater RO desalination unit of 30%, the average yearly fresh water production is estimated at 1450 m3 (or 4 m3 daily). Specific innovations of the system are: Low temperature thermal sources can be exploited efficiently for fresh water production; solar energy is used indirectly and does not heat the seawater; the RO unit is driven by mechanical work produced from the process; the system condenser acts as sea water pre-heater and this serves a double purpose; (1) increase of feed water temperature implies higher fresh water production (2) decrease of temperature of ''low temperature reservoir'' of Rankine cycle implies higher cycle efficiencies. (orig.)

  5. Optimisation robuste de turbines pour les cycles organiques de Rankine (ORC)

    OpenAIRE

    Bufi, Elio Antonio

    2016-01-01

    In recent years, the Organic Rankine Cycle (ORC) technology has received great interest from the scientific and technical community because of its capability to recover energy from low-grade heat sources. In some applications, as the Waste Heat Recovery (WHR), ORC plants need to be as compact as possible because of geometrical and weight constraints. Recently, these issues have been studied in order to promote the ORC technology for Internal Combustion Engine (ICE) applications. The idea to r...

  6. Thermodynamic Optimization of a Geothermal- Based Organic Rankine Cycle System Using an Artificial Bee Colony Algorithm

    OpenAIRE

    Osman Özkaraca; Pınar Keçebaş; Cihan Demircan; Ali Keçebaş

    2017-01-01

    Geothermal energy is a renewable form of energy, however due to misuse, processing and management issues, it is necessary to use the resource more efficiently. To increase energy efficiency, energy systems engineers carry out careful energy control studies and offer alternative solutions. With this aim, this study was conducted to improve the performance of a real operating air-cooled organic Rankine cycle binary geothermal power plant (GPP) and its components in the aspects of thermodynamic ...

  7. Working fluids selection for fishing boats waste heat powered organic Rankine-vapor compression ice maker

    Science.gov (United States)

    Bu, Xianbiao; Wang, Lingbao; Li, Huashan

    2014-10-01

    To utilize waste heat from fishing boats, an organic Rankine cycle/vapor compression cycle system was employed for ice making and a thermodynamic model was developed. Six working fluids were selected and compared in order to identify suitable working fluids which may yield high system efficiencies. The calculated results show that R600a is most suitable working fluid through comprehensive comparison of efficiency, size parameter, pressure ratio, coefficient of performance, system pressure and safety.

  8. Thermodynamic Analysis of a Rankine Cycle Powered Vapor Compression Ice Maker Using Solar Energy

    OpenAIRE

    Bing Hu; Xianbiao Bu; Weibin Ma

    2014-01-01

    To develop the organic Rankine-vapor compression ice maker driven by solar energy, a thermodynamic model was developed and the effects of generation temperature, condensation temperature, and working fluid types on the system performance were analyzed. The results show that the cooling power per square meter collector and ice production per square meter collector per day depend largely on generation temperature and condensation temperature and they increase firstly and then decrease with incr...

  9. Attitudes towards Mathematics at Secondary Level: Development and Structural Validation of the Scale for Assessing Attitudes towards Mathematics in Secondary Education (SAT-MAS)

    Science.gov (United States)

    Yáñez-Marquina, Lara; Villardón-Gallego, Lourdes

    2016-01-01

    Introduction: In secondary education, students' low achievement and engagement in mathematics are closely related to their attitudes towards the subject. Despite the international body of research, an exhaustive literature review of the existing instruments for measuring it draws attention to the inconsistency in the definition and corresponding…

  10. On the Rankin-Selberg method for higher genus string amplitudes

    CERN Document Server

    Florakis, Ioannis

    2017-01-01

    Closed string amplitudes at genus $h\\leq 3$ are given by integrals of Siegel modular functions on a fundamental domain of the Siegel upper half-plane. When the integrand is of rapid decay near the cusps, the integral can be computed by the Rankin-Selberg method, which consists of inserting an Eisenstein series $E_h(s)$ in the integrand, computing the integral by the orbit method, and finally extracting the residue at a suitable value of $s$. String amplitudes, however, typically involve integrands with polynomial or even exponential growth at the cusps, and a renormalization scheme is required to treat infrared divergences. Generalizing Zagier's extension of the Rankin-Selberg method at genus one, we develop the Rankin-Selberg method for Siegel modular functions of degree 2 and 3 with polynomial growth near the cusps. In particular, we show that the renormalized modular integral of the Siegel-Narain partition function of an even self-dual lattice of signature $(d,d)$ is proportional to a residue of the Langla...

  11. Thermodynamic Analysis of a Rankine Cycle Powered Vapor Compression Ice Maker Using Solar Energy

    Directory of Open Access Journals (Sweden)

    Bing Hu

    2014-01-01

    Full Text Available To develop the organic Rankine-vapor compression ice maker driven by solar energy, a thermodynamic model was developed and the effects of generation temperature, condensation temperature, and working fluid types on the system performance were analyzed. The results show that the cooling power per square meter collector and ice production per square meter collector per day depend largely on generation temperature and condensation temperature and they increase firstly and then decrease with increasing generation temperature. For every working fluid there is an optimal generation temperature at which organic Rankine efficiency achieves the maximum value. The cooling power per square meter collector and ice production per square meter collector per day are, respectively, 126.44 W m−2 and 7.61 kg m−2 day−1 at the generation temperature of 140°C for working fluid of R245fa, which demonstrates the feasibility of organic Rankine cycle powered vapor compression ice maker.

  12. Peat as Substrate for Small-Scale Constructed Wetlands Polishing Secondary Effluents from Municipal Wastewater Treatment Plant

    Directory of Open Access Journals (Sweden)

    Meng Jin

    2017-11-01

    Full Text Available With the recent development of constructed wetland technology, it has become a mainstream treatment technology for the mitigation of a variety of wastewaters. This study reports on the treatment performance and pH attenuation capacity of three different configurations of small-scale on-site surface flow constructed wetlands (SFCW: T1 (Peat + Typha latifolia, T2 (T. latifolia alone, and T3 (Peat alone treating secondary effluent from the Amherstview Water Pollution Control Plant (WPCP for two treatment periods (start-up period and operational period. The aim of this study was to compare the nutrients removal efficiencies between the different treatments, as well as to evaluate the effects of substrate and vegetation on the wetland system. For a hydraulic retention time of 2.5 days, the results showed that all treatment systems could attenuate the pH level during both the start-up and operational periods, while significant nutrient removal performance could only be observed during the operational period. Peat was noted to be a better SFCW substrate in promoting the removal of nitrate (NO3-N, total nitrogen (TN, and phosphorus. The addition of T. latifolia further enhanced NO3-N and TN removal efficiencies, but employing T. latifolia alone did not yield effluents that could meet the regulatory discharge limit (1.0 mg/L for phosphorus.

  13. The LA aggression scale for elementary school and upper secondary school students: Examination of psychometric properties of a new multidimensional measure of self- reported aggression

    Directory of Open Access Journals (Sweden)

    Kozina Ana

    2013-01-01

    Full Text Available The paper introduces a new multidimensional scale LA (lestvica agresivnosti [Aggression Scale] for measuring self-reported aggression in elementary and upper secondary school students in Slovenia. The scale has been developed with a special focus on the school setting, using three elementary school samples (preliminary study: N=2777; main study: N=10427 and validity and test-retest study: N=191 representative of 4th and 8th grade students in Slovenia and one upper secondary school sample (N=3253 representative of the final year of upper secondary school in Slovenia. The exploratory analyses using principal component analyses (PCA revealed a four-factor structure: verbal aggression, physical aggression, internal aggression and aggression towards authority that were interrelated. Confirmatory factor analyses (CFA showed that the items of the scale formed four factors that were related to the higher order factor. The structure turned out to be stable over different age groups. The scale demonstrated adequate internal consistency, concurrent validity and test-retest stability.

  14. Advanced Rankine and Brayton cycle power systems: Materials needs and opportunities

    Science.gov (United States)

    Grisaffe, S. J.; Guentert, D. C.

    1974-01-01

    Conceptual advanced potassium Rankine and closed Brayton power conversion cycles offer the potential for improved efficiency over steam systems through higher operating temperatures. However, for utility service of at least 100,000 hours, materials technology advances will be needed for such high temperature systems. Improved alloys and surface protection must be developed and demonstrated to resist coal combustion gases as well as potassium corrosion or helium surface degradation at high temperatures. Extensions in fabrication technology are necessary to produce large components of high temperature alloys. Long time property data must be obtained under environments of interest to assure high component reliability.

  15. Advanced Rankine and Brayton cycle power systems - Materials needs and opportunities

    Science.gov (United States)

    Grisaffe, S. J.; Guentert, D. C.

    1974-01-01

    Conceptual advanced potassium Rankine and closed Brayton power conversion cycles offer the potential for improved efficiency over steam systems through higher operating temperatures. However, for utility service of at least 100,000 hours, materials technology advances will be needed for such high temperature systems. Improved alloys and surface protection must be developed and demonstrated to resist coal combustion gases as well as potassium corrosion or helium surface degradation at high temperatures. Extensions in fabrication technology are necessary to produce large components of high temperature alloys. Long-time property data must be obtained under environments of interest to assure high component reliability.

  16. Experimental Comparison Of Working Fluids For Organic Rankine Cycle With Single-Screw Expander

    OpenAIRE

    Gusev, Sergei; Ziviani, Davide; Bell, Ian; De Paepe, Michel; van den Broek, Martijn

    2014-01-01

    This paper describes the behavior of an Organic Rankine Cycle (ORC) fed by a heat source with adaptable temperature and mass flow. For a suitable choice of working fluid, the setting of its evaporation pressure is crucial for the performance of an ORC installation. The higher the evaporation pressure, the higher the cycle efficiency on the one hand, but the lower the energy recovered from the heat source due to a higher outlet temperature on the other hand. An optimum has to be found to achie...

  17. Numerical Optimization of an Organic Rankine Cycle Scheme for Co-generation

    OpenAIRE

    Potenza, Marco; Naccarato, Fabrizio; Stigliano, Gianbattista; Risi, Arturo de

    2016-01-01

    The aim of the present work was the optimization of a small size Organic Rankine Cycle (ORC) system powered by a linear Parabolic Trough Collector (PTC) solar field by means of numerical model code developed on purpose. In the proposed scheme the solar energy is collected by a newly designed low cost PTC of 20m2 with a single tracking axis and it is concentrated on an opaque pipe collector in which flows as thermal fluid the Therminol® 66 oil. An oil-free scroll expander coupled with a 2 kW e...

  18. Theoretical study of thermally driven heat pumps based on double organic rankine cycle

    OpenAIRE

    Demierre, Jonathan; Favrat, Daniel

    2013-01-01

    Part of: Thermally driven heat pumps for heating and cooling. – Ed.: Annett Kühn – Berlin: Universitätsverlag der TU Berlin, 2013 ISBN 978-3-7983-2686-6 (print) ISBN 978-3-7983-2596-8 (online) urn:nbn:de:kobv:83-opus4-39458 [http://nbn-resolving.de/urn:nbn:de:kobv:83-opus4-39458] This study deals with a type of thermally driven heat pumps that consists of a reverse Rankine heat pump cycle, the compressor of which is driven by the turbine of a supercritical Organi...

  19. Uncertainty assessment of equations of state with application to an organic Rankine cycle

    DEFF Research Database (Denmark)

    Frutiger, Jerome; Bell, Ian; O’Connell, John P.

    2017-01-01

    Evaluations of equations of state (EoS) should include uncertainty. This study presents a genericmethod to analyse EoS from a detailed uncertainty analysis of the mathematical form and the dataused to obtain EoS parameter values. The method is illustrated by comparison of Soave–Redlich–Kwong (SRK......) cubic EoS with perturbed-chain statistical associating fluid theory (PC-SAFT) EoS for anorganic Rankine cycle (ORC) for heat recovery to power fromthe exhaust gas of a marine diesel engineusing cyclopentane as working fluid. Uncertainties of the EoS input parameters including...

  20. Conceptual design and analysis of a Dish-Rankine solar thermal power system

    Science.gov (United States)

    Pons, R. L.

    1980-08-01

    A Point Focusing Distributed Receiver (PFDR) solar thermal electric system which employs small Organic Rankine Cycle (ORC) engines is examined with reference to its projected technical/economic performance. With mass-produced power modules (about 100,000 per year), the projected life-cycle energy cost for an optimized no-storage system is estimated at 67 mills/kWh (Levelized Busbar Energy Cost) without the need for advanced development of any of its components. At moderate production rates (about 50 MWe/yr) system energy costs are competitive with conventional power generation systems in special remote-site types of applications.

  1. Panel cutting method: new approach to generate panels on a hull in Rankine source potential approximation

    Directory of Open Access Journals (Sweden)

    Hee-Jong Choi

    2011-12-01

    Full Text Available In the present study, a new hull panel generation algorithm, namely panel cutting method, was developed to predict flow phenomena around a ship using the Rankine source potential based panel method, where the iterative method was used to satisfy the nonlinear free surface condition and the trim and sinkage of the ship was taken into account. Numerical computations were performed to investigate the validity of the proposed hull panel generation algorithm for Series 60 (CB=0.60 hull and KRISO container ship (KCS, a container ship designed by Maritime and Ocean Engineering Research Institute (MOERI. The computational results were validated by comparing with the existing experimental data.

  2. Design and optimization of a novel organic Rankine cycle with improved boiling process

    DEFF Research Database (Denmark)

    Andreasen, Jesper Graa; Larsen, U.; Knudsen, Thomas

    2015-01-01

    to improve the boiling process. Optimizations are carried out for eight hydrocarbon mixtures for hot fluid inlet temperatures at 120 °C and 90 °C, using a genetic algorithm to determine the cycle conditions for which the net power output is maximized. The most promising mixture is an isobutane....../pentane mixture which, for the 90 °C hot fluid inlet temperature case, achieves a 14.5% higher net power output than an optimized organic Rankine cycle using the same mixture. Two parameter studies suggest that optimum conditions for the organic split-cycle are when the temperature profile allows the minimum...

  3. Performance analysis of different organic Rankine cycle configurations on board liquefied natural gas-fuelled vessels

    DEFF Research Database (Denmark)

    Baldasso, Enrico; Andreasen, Jesper Graa; Meroni, Andrea

    2017-01-01

    natural gas (LNG). The study compares the performance of six different ORC configurations both in design and off-design operation, and provides guidelines with respect to the most promising heat sources and sinks to be utilized by an ORC unit in order to maximize the annual fuel savings. In addition......Gas-fuelled shipping is expected to increase significantly in the coming years. Similarly, much effort is devoted to the study of waste heat recovery systems to be implemented on board ships. In this context, the organic Rankine cycle (ORC) technology is considered one of the most promising...

  4. Utilization of recently developed codes for high power Brayton and Rankine cycle power systems

    Science.gov (United States)

    Doherty, Michael P.

    1993-01-01

    Two recently developed FORTRAN computer codes for high power Brayton and Rankine thermodynamic cycle analysis for space power applications are presented. The codes were written in support of an effort to develop a series of subsystem models for multimegawatt Nuclear Electric Propulsion, but their use is not limited just to nuclear heat sources or to electric propulsion. Code development background, a description of the codes, some sample input/output from one of the codes, and state future plans/implications for the use of these codes by NASA's Lewis Research Center are provided.

  5. Preliminary design package for residential heating/cooling system--Rankine air conditioner redesign

    Energy Technology Data Exchange (ETDEWEB)

    1978-12-01

    This report contains a summary of the preliminary redesign and development of a marketable single-family heating and cooling system. The objectives discussed are the interim design and schedule status of the Residential (3-ton) redesign, problem areas and solutions, and the definition of plans for future design and development activities. The proposed system for a single-family residential heating and cooling system is a single-loop, solar-assisted, hydronic-to-warm-air heating subsystem with solar-assisted domestic water heating and a Rankine-driven expansion air-conditioning subsystem.

  6. Final Report: Modifications and Optimization of the Organic Rankine Cycle to Improve the Recovery of Waste Heat

    Energy Technology Data Exchange (ETDEWEB)

    Guillen, Donna Post [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zia, Jalal [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2013-09-01

    This research and development (R&D) project exemplifies a shared public private commitment to advance the development of energy efficient industrial technologies that will reduce the U.S. dependence upon foreign oil, provide energy savings and reduce greenhouse gas emissions. The purpose of this project was to develop and demonstrate a Direct Evaporator for the Organic Rankine Cycle (ORC) for the conversion of waste heat from gas turbine exhaust to electricity. In conventional ORCs, the heat from the exhaust stream is transferred indirectly to a hydrocarbon based working fluid by means of an intermediate thermal oil loop. The Direct Evaporator accomplishes preheating, evaporation and superheating of the working fluid by a heat exchanger placed within the exhaust gas stream. Direct Evaporation is simpler and up to 15% less expensive than conventional ORCs, since the secondary oil loop and associated equipment can be eliminated. However, in the past, Direct Evaporation has been avoided due to technical challenges imposed by decomposition and flammability of the working fluid. The purpose of this project was to retire key risks and overcome the technical barriers to implementing an ORC with Direct Evaporation. R&D was conducted through a partnership between the Idaho National Laboratory (INL) and General Electric (GE) Global Research Center (GRC). The project consisted of four research tasks: (1) Detailed Design & Modeling of the ORC Direct Evaporator, (2) Design and Construction of Partial Prototype Direct Evaporator Test Facility, (3) Working Fluid Decomposition Chemical Analyses, and (4) Prototype Evaluation. Issues pertinent to the selection of an ORC working fluid, along with thermodynamic and design considerations of the direct evaporator, were identified. The FMEA (Failure modes and effects analysis) and HAZOP (Hazards and operability analysis) safety studies performed to mitigate risks are described, followed by a discussion of the flammability analysis of the

  7. Detection of multi-scale secondary flow structures using anisotropic 2D Ricker wavelets in a bent tube model for curved arteries

    Science.gov (United States)

    Plesniak, Daniel H.; Bulusu, Kartik V.; Plesniak, Michael W.

    2012-11-01

    Interpretation of complex flow patterns observed in this study of a model curved artery required characterization of multiple, low-circulation secondary flow structures that were observed during the late systolic deceleration and diastolic phases under physiological inflow conditions. Phase-locked, planar vorticity PIV data were acquired at various cross-sectional locations of the 180-degree bent tube model. High circulation, deformed Dean- and Lyne-type vortices were observed during early stages of deceleration, while several smaller scale, highly deformed, low-circulation vortical patterns appeared in the core and near-wall regions during late systolic deceleration and diastolic phases. Due to the multiplicity of vortical scales and shapes, anisotropic 2D Ricker wavelets were used for coherent structure detection in a continuous wavelet transform algorithm (PIVlet 1.2). Our bio-inspired study is geared towards understanding whether optimizing the shape of the wavelet kernel will enable better resolution of several low-circulation, multi-scale secondary flow morphologies and whether new insights into the dynamics of arterial secondary flow structures can accordingly be gained. Supported by the National Science Foundation, Grant No. CBET-0828903 and GW Center for Biomimetics and Bioinspired Engineering (COBRE).

  8. Research of efficiency of the organic Rankine cycle on a mathematical model

    Directory of Open Access Journals (Sweden)

    Galashov N.

    2017-01-01

    Full Text Available The object of the study are the organic Rankine cycle. The purpose of research is to evaluate the impact on the net efficiency of the initial and final properties of the cycle at work on a saturated and superheated steam. Investigations were carried out on the basis of a mathematical model, in which the thermodynamic properties of materials are determined on the basis of “REFPROP”. On the basis of the available scientific publications on the use of working fluids in an organic Rankine cycle analysis was selected ozone-safe pentane. A mathematical model has been developed on condition that condenser is used as air cooler which allows the substance to condense at a temperature below 0 °С. Numerical study on the mathematical model shown that net efficiency at work on pentane linearly depends on the condensation temperature and parabolically depends on the initial temperature with the saturated steam. During work at the superheated steam efficiency strongly depends on both the initial temperature and of the initial pressure. With rising initial temperature is necessary to gradually increase the initial pressure under certain conditions.

  9. Multi-Objective Optimization of Organic Rankine Cycle Power Plants Using Pure and Mixed Working Fluids

    Directory of Open Access Journals (Sweden)

    Jesper G. Andreasen

    2016-04-01

    Full Text Available For zeotropic mixtures, the temperature varies during phase change, which is opposed to the isothermal phase change of pure fluids. The use of such mixtures as working fluids in organic Rankine cycle power plants enables a minimization of the mean temperature difference of the heat exchangers, which is beneficial for cycle performance. On the other hand, larger heat transfer surface areas are typically required for evaporation and condensation when zeotropic mixtures are used as working fluids. In order to assess the feasibility of using zeotropic mixtures, it is, therefore, important to consider the additional costs of the heat exchangers. In this study, we aim at evaluating the economic feasibility of zeotropic mixtures compared to pure fluids. We carry out a multi-objective optimization of the net power output and the component costs for organic Rankine cycle power plants using low-temperature heat at 90 ∘ C to produce electrical power at around 500 kW. The primary outcomes of the study are Pareto fronts, illustrating the power/cost relations for R32, R134a and R32/R134a (0.65/0.35 mole . The results indicate that R32/R134a is the best of these fluids, with 3.4 % higher net power than R32 at the same total cost of 1200 k$.

  10. Selecting working fluids in an organic Rankine cycle for power generation from low temperature heat sources

    Directory of Open Access Journals (Sweden)

    Fredy Vélez

    2014-01-01

    Full Text Available Este trabajo presenta un estudio termodinámico realizado sobre el uso de fuentes de calor de baja temperatura para la generaci ón de energía a través de un ciclo Rankin e subcrítico con fluidos de trabajo orgánicos. Un análisis d el estado del arte de esta tecn ología muestra como línea de investigación abierta, la selección del fluido de trabajo, pues hasta ahora, no existe un fluido que satisfaga t odos los aspectos medioambientales y técnicos a tener en cuenta en estos ciclos. Por ello, se ha desarrollado una serie de simulaciones que permiten estudiar el comportamiento del ciclo Rankine con difer entes configuraciones y fluidos (húmedo, seco e isoentrópico, permitiendo con ello observar de qué manera influyen cambios ta nto en esos tipos de fluidos utilizados (refrigerantes, hidroca rburos y agua, como de condiciones de temperatura, presión, flujo, etc. , sobre la eficiencia total del ciclo. Con el trabajo realizado se demuestra la viabilidad de este tipo de proceso en la recuperación de calore s en la industria y/o aprovechamiento de fuentes renovables de baja y media temperatura para la producción de energía eléctrica.

  11. Waste Heat Recovery of a PEMFC System by Using Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Tianqi He

    2016-04-01

    Full Text Available In this study, two systems are brought forward to recover the waste heat of a proton exchange membrane fuel cell (PEMFC, which are named the organic Rankine cycle (ORC, and heat pump (HP combined organic Rankine cycle (HPORC. The performances of both systems are simulated on the platform of MATLAB with R123, R245fa, R134a, water, and ethanol being selected as the working fluid, respectively. The results show that, for PEMFC where operating temperature is constantly kept at 60 °C, there exists an optimum working temperature for each fluid in ORC and HPORC. In ORC, the maximal net power can be achieved with R245fa being selected as the working fluid. The corresponding thermal efficiency of the recovery system is 4.03%. In HPORC, the maximal net power can be achieved with water being selected in HP and R123 in ORC. The thermal efficiency of the recovery system increases to 4.73%. Moreover, the possibility of using ORC as the cooling system of PEMFC is also studied. The heat released from PEMFC stack is assumed to be wholly recovered by the ORC or HPORC system. The results indicate that the HPORC system is much more feasible for the cooling system of a PEMFC stack, since the heat recovery ability can be promoted due to the presence of HP.

  12. Self-beliefs mediate mathematical performance between primary and lower secondary school: A large scale longitudinal cohort study

    NARCIS (Netherlands)

    Reed, Helen; Kirschner, Paul A.; Jolles, Jelle

    2016-01-01

    It is often argued that enhancement of self-beliefs should be one of the key goals ofeducation. However, very little is known about the relation between self-beliefs and performance when students move from primary to secondary school in highly differentiated educational systems with early tracking.

  13. The Practice of Scaling down Practical Assessment Components of Agriculture in Junior Secondary Schools Curriculum: A Synthesis of Teachers Perceptions

    Science.gov (United States)

    Hulela, Keba

    2017-01-01

    This ethnographic research study aimed at investigating factors that contributed to the decline in the number of practical assessed projects in junior secondary agricultural education assessment in Botswana. Participant-observation technique was used to gather data in the form of field notes from in-service teachers at BCA and in-school teachers…

  14. Indoor Secondary Pollutants from Household Product Emissions inthe Presence of Ozone: A Bench-Scale Chamber Study

    Energy Technology Data Exchange (ETDEWEB)

    Destaillats, Hugo; Lunden, Melissa M.; Singer, Brett C.; Coleman,Beverly K.; Hodgson, Alfred T.; Weschler, Charles J.; Nazaroff, William W.

    2005-10-01

    Ozone-driven chemistry is a major source of indoor secondary pollutants of health concern. This study investigates secondary air pollutants formed from reactions between constituents of household products and ozone. Gas-phase product emissions were introduced along with ozone at constant rates into a 198-L Teflon-lined reaction chamber. Gas-phase concentrations of reactive terpenoids and oxidation products were measured. Formaldehyde was a predominant oxidation byproduct for the three studied products, with yields under most conditions of 20-30% with respect to ozone consumed. Acetaldehyde, acetone, glycolaldehyde, formic acid and acetic acid were each also detected for two or three of the products. Immediately upon mixing of reactants, a scanning mobility particle sizer detected particle nucleation events that were followed by a significant degree of ultrafine particle growth. The production of secondary gaseous pollutants and particles depended primarily on the ozone level and was influenced by other parameters such as the air-exchange rate. Hydroxyl radical concentrations in the range 0.04-200 x 10{sup 5} molecules cm{sup -3} were measured. OH concentrations were observed to vary strongly with residual ozone level in the chamber, which was in the range 1-25 ppb, as is consistent with expectations from a simplified kinetic model. In a separate test, we exposed the dry residue of two products to ozone in the chamber and observed the formation of gas-phase and particle-phase secondary oxidation products.

  15. Comparison of a Novel Organic-Fluid Thermofluidic Heat Converter and an Organic Rankine Cycle Heat Engine

    Directory of Open Access Journals (Sweden)

    Christoph J.W. Kirmse

    2016-06-01

    Full Text Available The Up-THERM heat converter is an unsteady, two-phase thermofluidic oscillator that employs an organic working fluid, which is currently being considered as a prime-mover in small- to medium-scale combined heat and power (CHP applications. In this paper, the Up-THERM heat converter is compared to a basic (sub-critical, non-regenerative organic Rankine cycle (ORC heat engine with respect to their power outputs, thermal efficiencies and exergy efficiencies, as well as their capital and specific costs. The study focuses on a pre-specified Up-THERM design in a selected application, a heat-source temperature range from 210 °C to 500 °C and five different working fluids (three n-alkanes and two refrigerants. A modeling methodology is developed that allows the above thermo-economic performance indicators to be estimated for the two power-generation systems. For the chosen applications, the power output of the ORC engine is generally higher than that of the Up-THERM heat converter. However, the capital costs of the Up-THERM heat converter are lower than those of the ORC engine. Although the specific costs (£/kW of the ORC engine are lower than those of the Up-THERM converter at low heat-source temperatures, the two systems become progressively comparable at higher temperatures, with the Up-THERM heat converter attaining a considerably lower specific cost at the highest heat-source temperatures considered.

  16. Selection and optimization of pure and mixed working fluids for low grade heat utilization using organic Rankine cycles

    DEFF Research Database (Denmark)

    Andreasen, Jesper Graa; Larsen, Ulrik; Knudsen, Thomas

    2014-01-01

    We present a generic methodology for organic Rankine cycle optimization, where the working fluid is included as an optimization parameter, in order to maximize the net power output of the cycle. The method is applied on two optimization cases with hot fluid inlet temperatures at 120°C and 90°C. P...

  17. Thermodynamic analysis of an integrated gasification solid oxide fuel cell plant combined with an organic Rankine cycle

    DEFF Research Database (Denmark)

    Pierobon, Leonardo; Rokni, Masoud; Larsen, Ulrik

    2013-01-01

    into a fixed bed gasification plant to produce syngas which fuels the combined solid oxide fuel cells e organic Rankine cycle system to produce electricity. More than a hundred fluids are considered as possible alternative for the organic cycle using non-ideal equations of state (or state-of-the-art equations...

  18. Multi-objective optimization of organic Rankine cycle power plants using pure and mixed working fluids

    DEFF Research Database (Denmark)

    Andreasen, Jesper Graa; Kærn, Martin Ryhl; Pierobon, Leonardo

    2015-01-01

    For zeotropic mixtures, the temperature varies during phase change, which is opposed to the isothermalphase change of pure fluids. The use of such mixtures as working fluids in organic Rankine cyclepower plants enables a minimization of the mean temperature difference of the heat exchangers whenthe...... mixturesare usually degraded compared to an ideal mixture heat transfer coefficient linearly interpolatedbetween the pure fluid values. This entails a need for larger and more expensive heat exchangers. Previousstudies primarily focus on the thermodynamic benefits of zeotropic mixtures by employing firstand...... second law analyses. In order to assess the feasibility of using zeotropic mixtures, it is, however,important to consider the additional costs of the heat exchangers. In this study, we aim at evaluatingthe economic feasibility of zeotropic mixtures compared to pure fluids. We carry out a multi...

  19. Working fluid selection for organic Rankine cycles - Impact of uncertainty of fluid properties

    DEFF Research Database (Denmark)

    Frutiger, Jerome; Andreasen, Jesper Graa; Liu, Wei

    2016-01-01

    This study presents a generic methodology to select working fluids for ORC (Organic Rankine Cycles)taking into account property uncertainties of the working fluids. A Monte Carlo procedure is described as a tool to propagate the influence of the input uncertainty of the fluid parameters on the ORC...... modeloutput, and provides the 95%-confidence interval of the net power output with respect to the fluid property uncertainties. The methodology has been applied to a molecular design problem for an ORCusing a low-temperature heat source and consisted of the following four parts: 1) formulation...... of processmodels and constraints 2) selection of property models, i.e. Penge Robinson equation of state 3)screening of 1965 possible working fluid candidates including identification of optimal process parametersbased on Monte Carlo sampling 4) propagating uncertainty of fluid parameters to the ORC netpower output...

  20. Parametric theoretical study of a two-stage solar organic Rankine cycle for RO desalination

    Energy Technology Data Exchange (ETDEWEB)

    Kosmadakis, G.; Manolakos, D.; Papadakis, G. [Department of Natural Resources and Agricultural Engineering, Agricultural University of Athens, 75 Iera Odos Street, 11855 Athens (Greece)

    2010-05-15

    The present work concerns the parametric study of an autonomous, two-stage solar organic Rankine cycle for RO desalination. The main goal of the current simulation is to estimate the efficiency, as well as to calculate the annual mechanical energy available for desalination in the considered cases, in order to evaluate the influence of various parameters on the performance of the system. The parametric study concerns the variation of different parameters, without changing actually the baseline case. The effect of the collectors' slope and the total number of evacuated tube collectors used, have been extensively examined. The total cost is also taken into consideration and is calculated for the different cases examined, along with the specific fresh water cost (EUR/m{sup 3}). (author)

  1. Comparative investigation of working fluids for an organic Rankine cycle with geothermal water

    Science.gov (United States)

    Liu, Yan-Na; Xiao, Song

    2015-06-01

    In this paper, the thermodynamic investigation on the use of geothermal water (130 °C as maximum) for power generation through a basic Rankine has been presented together with obtained main results. Six typical organic working fluids (i.e., R245fa, R141b, R290, R600, R152a, and 134a) were studied with modifying the input pressure and temperature to the turbine. The results show that there are no significant changes taking place in the efficiency for these working fluids with overheating the inlet fluid to the turbine, i.e., efficiency is a weak function of temperature. However, with the increasing of pressure ratio in the turbine, the efficiency rises more sharply. The technical viability is shown of implementing this type of process for recovering low temperature heat resource.

  2. Effectiveness of Operation of Organic Rankine Cycle Installation Applied in the Liquid Natural Gas Regasification Plant

    Science.gov (United States)

    Kaczmarek, R.; Stachel, A. A.

    2017-05-01

    An analysis of the operation of an Organic Rankine Cycle (ORC) installation heated by a low-temperature heat source is presented for the case where a condenser of a working fluid is cooled by a liquid of ultralow temperature. For this purpose, the process of regasification of liquid natural gas (LNG) is considered. In the process, the condensation heat of the working fluid in ORC is taken by the LNG evaporating subsequently (i.e., undergoing regasification). The paper presents the schematic of this installation and its application, as well as the results of calculations on the basis of the analysis in terms of the power and efficiency. In the analysis, organic fluids used in the ORC as working ones have been selected.

  3. Linear Active Disturbance Rejection Control of Waste Heat Recovery Systems with Organic Rankine Cycles

    Directory of Open Access Journals (Sweden)

    Fang Fang

    2012-12-01

    Full Text Available In this paper, a linear active disturbance rejection controller is proposed for a waste heat recovery system using an organic Rankine cycle process, whose model is obtained by applying the system identification technique. The disturbances imposed on the waste heat recovery system are estimated through an extended linear state observer and then compensated by a linear feedback control strategy. The proposed control strategy is applied to a 100 kW waste heat recovery system to handle the power demand variations of grid and process disturbances. The effectiveness of this controller is verified via a simulation study, and the results demonstrate that the proposed strategy can provide satisfactory tracking performance and disturbance rejection.

  4. Draft report: application of organic Rankine cycle heat recovery systems to diesel powered marine vessels

    Energy Technology Data Exchange (ETDEWEB)

    1977-07-15

    The analysis and results of an investigation of the application of organic Rankine cycle heat recovery systems to diesel-powered marine vessels are described. The program under which this study was conducted was sponsored jointly by the US Energy Research and Development Administration, the US Navy, and the US Maritime Administration. The overall objective of this study was to investigate diesel bottoming energy recovery systems, currently under development by three US concerns, to determine the potential for application to marine diesel propulsion and auxiliary systems. The study primarily focused on identifying the most promising vessel applications (considering vessel type, size, population density, operational duty cycle, etc.) so the relative economic and fuel conservation merits of energy recovery systems could be determined and assessed. Vessels in the current fleet and the projected 1985 fleet rated at 1000 BHP class and above were investigated.

  5. Thermal Stability of Hexamethyldisiloxane (MM for High-Temperature Organic Rankine Cycle (ORC

    Directory of Open Access Journals (Sweden)

    Markus Preißinger

    2016-03-01

    Full Text Available The design of efficient Organic Rankine Cycle (ORC units for the usage of industrial waste heat at high temperatures requires direct contact evaporators without intermediate thermal oil circuits. Therefore, the thermal stability of high-temperature working fluids gains importance. In this study, the thermal degradation of hexamethyldisiloxane (MM is investigated in an electrically heated tube. Qualitative results concerning remarks on degradation products as well as quantitative results like the annual degradation rate are presented. It is shown that MM is stable up to a temperature of 300 °C with annual degradation rates of less than 3.5%. Furthermore, the break of a silicon–carbon bond can be a main chemical reaction that influences the thermal degradation. Finally, it is discussed how the results may impact the future design of ORC units.

  6. Rankine cycle condenser pressure control using an energy conversion device bypass valve

    Science.gov (United States)

    Ernst, Timothy C; Nelson, Christopher R; Zigan, James A

    2014-04-01

    The disclosure provides a waste heat recovery system and method in which pressure in a Rankine cycle (RC) system of the WHR system is regulated by diverting working fluid from entering an inlet of an energy conversion device of the RC system. In the system, an inlet of a controllable bypass valve is fluidly coupled to a working fluid path upstream of an energy conversion device of the RC system, and an outlet of the bypass valve is fluidly coupled to the working fluid path upstream of the condenser of the RC system such that working fluid passing through the bypass valve bypasses the energy conversion device and increases the pressure in a condenser. A controller determines the temperature and pressure of the working fluid and controls the bypass valve to regulate pressure in the condenser.

  7. Organic Rankine cycle unit for waste heat recovery on ships (PilotORC)

    DEFF Research Database (Denmark)

    Haglind, Fredrik; Montagud, Maria E. Mondejar; Andreasen, Jesper Graa

    The project PilotORC was aimed at evaluating the technical and economic feasibility of the use of organic Rankine cycle (ORC) units to recover low-temperature waste heat sources (i.e. exhaust gases, scavenge air, engine cooling system, and lubricant oil system) on container vessels. The project...... included numerical simulations and experimental tests on a 125 kW demonstration ORC unit that utilizes the waste heat of the main engine cooling system on board one of Mærsk's container vessels. During the design of the demonstration ORC unit, different alternatives for the condenser were analyzed in order...... to minimize the size of the heat exchanger area. Later on the ORC unit was successfully installed on board, and it has been working uninterruptedly since, demonstrating the matureness of the ORC technology for maritime applications. During the onboard testing, additional measuring devices were installed...

  8. Recent research trends in organic Rankine cycle technology: A bibliometric approach

    DEFF Research Database (Denmark)

    Imran, Muhammad; Haglind, Fredrik; Asim, Muhammad

    2018-01-01

    Expanded. Different aspects of the publications were analyzed, such as publication type, major research areas, journals, citations, authorship pattern, affiliations as well as the keyword occurrence frequency. The impact factor, h-index and number of citations were used to investigate the strength...... of active countries, institutes, authors, and journals in the organic Rankine cycle technology field. From 2000 to 2016, there were 2120 articles published by 3443 authors from 997 research institutes scattered over 71 countries. The total number of citations and impact factor are 36,739 and 4597......, respectively, corresponding to 17 citations per paper and an impact factor of 2.168 per publication. The research articles originate primarily from China, the USA, and European countries. Results indicate that China, the United States, Italy, Greece, Belgium, Spain, Germany and the United Kingdom...

  9. Control system to a Rankine cycle with a Tesla turbine using arduino

    Energy Technology Data Exchange (ETDEWEB)

    Medeiros, Josenei G., E-mail: joseneigodoi@yahoo.com.br [Faculdade de Tecnologia Sao Francisco (FATESF), Jacarei, SP (Brazil); Guimaraes, Lamartine F.; Placco, Guilherme M., E-mail: guimarae@ieav.cta.br, E-mail: placco@ieav.cta.br [Instituto de Estudos Avancados (ENU/IEAv/DCTA), Sao Jose dos Campos, SP (Brazil). Departamento de Energia Nuclear

    2013-07-01

    The thermal Rankine cycle is a thermodynamic cycle which converts heat in energy. This cycle occurs in steady state, in other words the cycle is a closed loop circuit with continuous feedback, which guarantees the reuse process one energy transformed in the various stages of the cycle. This cycle is used to drive a turbine type TESLA designed for the system. The objective of this work is to create the control and automation of this cycle using an micro-controlled system with Arduino that will hold the collection of sensors and the system will act to maintain the balance of the cycle causing it to behave continuously and with less interference from human operation for maintenance. Data will be collected and further processed, where it will display all the sensors and the situation of the actuators involved. Using Arduino system ensures the stability and reliability with a low cost of implementation.

  10. Thermodynamic Analysis of an Integrated Solid Oxide Fuel Cell Cycle with a Rankine Cycle

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2010-01-01

    Hybrid systems consisting of Solid Oxide Fuel Cells (SOFC) on the top of a Steam Turbine (ST) are investigated. The plants are fired by natural gas (NG). A desulfurization reactor removes the sulfur content in the fuel while a pre-reformer breaks down the heavier hydrocarbons. The pre-treated fuel...... enters then into the anode side of the SOFC. The remaining fuels after the SOFC stacks enter a burner for further burning. The off-gases are then used to produce steam for a Rankine cycle in a Heat Recovery Steam Generator (HRSG). Different system setups are suggested. Cyclic efficiencies up to 67......% are achieved which is considerably higher than the conventional Combined Cycles (CC). Both ASR (Adiabatic Steam Reformer) and CPO (Catalytic Partial Oxidation) fuel pre-reformer reactors are considered in this investigation....

  11. Computer modeling of a regenerative solar-assisted Rankine power cycle

    Science.gov (United States)

    Lansing, F. L.

    1977-01-01

    A detailed interpretation of the computer program that describes the performance of one of these cycles; namely, a regenerative Rankine power cycle is presented. Water is used as the working medium throughout the cycle. The solar energy collected at relatively low temperature level presents 75 to 80% of the total heat demand and provides mainly the latent heat of vaporization. Another energy source at high temperature level superheats the steam and supplements the solar energy share. A program summary and a numerical example showing the sequency of computations are included. The outcome from the model comprises line temperatures, component heat rates, specific steam consumption, percentage of solar energy contribution, and the overall thermal efficiency.

  12. Analysis and optimization of the low-temperature solar organic Rankine cycle (ORC)

    Energy Technology Data Exchange (ETDEWEB)

    Delgado-Torres, Agustin M. [Dpto. Fisica Fundamental y Experimental, Electronica y Sistemas, Escuela Tecnica Superior de Ingenieria Civil e Industrial, Universidad de La Laguna (ULL), Avda, Astrofisico Francisco Sanchez s/n, 38206 La Laguna, Tenerife (Spain); Garcia-Rodriguez, Lourdes [Dpto. Ingenieria Energetica, Escuela Tecnica Superior de Ingenieros, Universidad de Sevilla, Camino de los Descubrimientos, s/n 41092 Sevilla (Spain)

    2010-12-15

    Solar thermal driven reverse osmosis desalination is a promising renewable energy-driven desalination technology. A joint use of the solar thermal powered organic Rankine cycle (ORC) and the desalination technology of less energy consumption, reverse osmosis (RO), makes this combination interesting in some scarce water resource scenarios. However, prior to any practical experience with any new process, a comprehensive and rigorous theoretical study must be done in order to assess the performance of the new technology or combination of existing technologies. The main objective of the present paper is the expansion of the theoretical analysis done by the authors in previous works to the case in which the thermal energy required by a solar ORC is supplied by means of stationary solar collectors. Twelve substances are considered as working fluids of the ORC and four different models of stationary solar collectors (flat plate collectors, compound parabolic collectors and evacuated tube collectors) are also taken into account. Operating conditions of the solar ORC that minimizes the aperture area needed per unit of mechanical power output of the solar cycle are determined for every working fluid and every solar collector. The former is done considering a direct vapour generation configuration of the solar cycle and also the configuration with water as heat transfer fluid flowing inside the solar collector. This work is part of the theoretical analysis of the solar thermal driven seawater and brackish water reverse osmosis desalination technology. Nevertheless, the supplied information can be also used for the assessment of different applications of the solar ORC. In that case, results presented in this paper can be useful in techno-economic analysis, selection of working fluids of the Rankine cycle, sizing of systems and assessment of solar power cycle configuration. (author)

  13. Critical Evaluation of the Jackson/Cubbin Pressure Ulcer Risk Scale - A Secondary Analysis of a Retrospective Cohort Study Population of Intensive Care Patients.

    Science.gov (United States)

    Ahtiala, Maarit H; Soppi, Esa; Kivimäki, Riku

    2016-02-01

    Although the Jackson/Cubbin pressure ulcer (PU) risk scale performs best among risk scales used in intensive care units (ICUs), its performance was not fully satisfactory. In 2010, a minimally modified Jackson/Cubbin (mJ/C) PU risk scale was introduced to formalize PU risk assessment in a large medical-surgical ICU in Finland. The purpose of this secondary analysis was to examine whether individual categories of the mJ/C scale have similar weight and whether the scores within each category (from 1 to 4; 1 equaling highest risk and 4 equaling lowest risk) are linear, as is assumed for the original and modified scales. Using data from a cohort of 1,616 consecutively admitted patients retrieved from the ICU database, a detailed secondary analysis of each of the 12 main scoring categories of the Jackson/Cubbin risk scale was performed using logistic regression and analysis of linearity and weight. Of the 1,616 admitted patients, 168 developed a PU during their ICU stay. Among the risk categories, body mass index, nutrition, respiration, age, and transportation during the 48 hours before scoring did not contribute significantly (P >0.05) to the total risk score or the actual development of a PU. The 7 other main categories - incontinence, mobility, medical history, oxygen requirement, need for assistance with hygiene, hemodynamics, and general skin condition - were the main risk contributors. Although only the linearity of the different categories correlated significantly with the predictive value of the categories, the linearity as well as the weights of the categories were at variance from what was assumed originally. The mJ/C scale needs refinement to be a more accurate instrument for PU risk assessment of ICU patients. Not all mJ/C categories were found to contribute to the risk and, when they do, their weight and linearity vary from what has been assumed. The categories respiration and oxygen requirement and the categories mental condition, mobility, and hygiene

  14. Psychometric properties of the Satisfaction with Life Scale (SWLS): secondary analysis of the Mexican Health and Aging Study.

    Science.gov (United States)

    López-Ortega, Mariana; Torres-Castro, Sara; Rosas-Carrasco, Oscar

    2016-12-09

    The Satisfaction with Life Scale (SWLS) has been widely used and has proven to be a valid and reliable instrument for assessing satisfaction with life in diverse population groups, however, research on satisfaction with life and validation of different measuring instruments in Mexican adults is still lacking. The objective was to evaluate the psychometric properties of the Satisfaction with Life Scale (SWLS) in a representative sample of Mexican adults. This is a methodological study to evaluate a satisfaction with life scale in a sample of 13,220 Mexican adults 50 years of age or older from the 2012 Mexican Health and Aging Study. The scale's reliability (internal consistency) was analysed using Cronbach's alpha and inter-item correlations. An exploratory factor analysis was also performed. Known-groups validity was evaluated comparing good-health and bad-health participants. Comorbidity, perceived financial situation, self-reported general health, depression symptoms, and social support were included to evaluate the validity between these measures and the total score of the scale using Spearman's correlations. The analysis of the scale's reliability showed good internal consistency (α = 0.74). The exploratory factor analysis confirmed the existence of a unique factor structure that explained 54% of the variance. SWLS was related to depression, perceived health, financial situation, and social support, and these relations were all statistically significant (P life satisfaction between the good- and bad-health groups. Results show good internal consistency and construct validity of the SWLS. These results are comparable with results from previous studies. Meeting the study's objective to validate the scale, the results show that the Spanish version of the SWLS is a reliable and valid measure of satisfaction with life in the Mexican context.

  15. RNA-TVcurve: a Web server for RNA secondary structure comparison based on a multi-scale similarity of its triple vector curve representation.

    Science.gov (United States)

    Li, Ying; Shi, Xiaohu; Liang, Yanchun; Xie, Juan; Zhang, Yu; Ma, Qin

    2017-01-21

    RNAs have been found to carry diverse functionalities in nature. Inferring the similarity between two given RNAs is a fundamental step to understand and interpret their functional relationship. The majority of functional RNAs show conserved secondary structures, rather than sequence conservation. Those algorithms relying on sequence-based features usually have limitations in their prediction performance. Hence, integrating RNA structure features is very critical for RNA analysis. Existing algorithms mainly fall into two categories: alignment-based and alignment-free. The alignment-free algorithms of RNA comparison usually have lower time complexity than alignment-based algorithms. An alignment-free RNA comparison algorithm was proposed, in which novel numerical representations RNA-TVcurve (triple vector curve representation) of RNA sequence and corresponding secondary structure features are provided. Then a multi-scale similarity score of two given RNAs was designed based on wavelet decomposition of their numerical representation. In support of RNA mutation and phylogenetic analysis, a web server (RNA-TVcurve) was designed based on this alignment-free RNA comparison algorithm. It provides three functional modules: 1) visualization of numerical representation of RNA secondary structure; 2) detection of single-point mutation based on secondary structure; and 3) comparison of pairwise and multiple RNA secondary structures. The inputs of the web server require RNA primary sequences, while corresponding secondary structures are optional. For the primary sequences alone, the web server can compute the secondary structures using free energy minimization algorithm in terms of RNAfold tool from Vienna RNA package. RNA-TVcurve is the first integrated web server, based on an alignment-free method, to deliver a suite of RNA analysis functions, including visualization, mutation analysis and multiple RNAs structure comparison. The comparison results with two popular RNA

  16. Small-scale combined heat and power as a balancing reserve for wind – The case of participation in the German secondary control reserve

    Directory of Open Access Journals (Sweden)

    Peter Sorknæs

    2014-06-01

    Full Text Available Increasing amounts of intermittent renewable energy sources (RES are being integrated into energy systems worldwide. Due to the nature of these sources, they are found to increase the importance of mechanisms for balancing the electricity system. Small-scale combined heat and power (CHP plants based on gas have proven their ability to participate in the electricity system balancing, and can hence be used to facilitate an integration of intermittent RES into electricity systems. Within the EU electricity system, balancing reserves have to be procured on a market basis. This paper investigates the ability and challenges of a small-scale CHP plant based on natural gas to participate in the German balancing reserve for secondary control. It is found that CHP plants have to account for more potential losses than traditional power plants. However, it is also found that the effect of these losses can be reduced by increasing the flexibility of the CHP unit.

  17. A Multicenter Study Using the SWAG Scale to Compare Secondary Alveolar Bone Graft Outcomes for Patients With Cleft Lip and Palate.

    Science.gov (United States)

    Russell, Kathleen; Long, Ross E; Daskalogiannakis, John; Mercado, Ana; Hathaway, Ronald; Semb, Gunvor; Shaw, William

    2016-03-01

    Objective To assess secondary alveolar bone graft (ABG) outcomes using the standardized way to assess grafts, or SWAG scale, for patients with cleft lip and palate (CLP). Design Retrospective cohort study. Setting Four cleft centers with different protocols. Methods One hundred sixty maxillary occlusal radiographs taken 3 to 18 months after secondary ABG for sequentially treated patients with CLP were assessed using the SWAG scale. Radiographs were scanned, standardized, blinded, and rated by six orthodontists using the SWAG scale. Randomized radiographs were rated twice, 24 hours apart, by the same raters. Main Outcomes Intrarater and interrater reliabilities were assessed. Means and SDs were calculated for ABG ratings using analysis of variance and Tukey tests (P < .05). Result The mean ABG age was 9.1 years (range = 7 to 10.1 years) and the mean follow-up age was 12.4 years (range = 8.2 to 20.4 years). Intrarater and interrater reliabilities were good (intrarater = 0.788, interrater = 0.705), and higher than published methods. Mean ABG ratings for the cleft centers were 4.53, 2.9, 3.63, and 5.0 and differed significantly. The two centers with the highest ABG ratings showed higher ratings for all thirds decreasing from apical to coronal. The two centers with lower ABG ratings showed poorer ABG ratings for all thirds, and the middle third received the highest ratings. Conclusions The SWAG scale overcomes the challenges of age and bone location. The SWAG method was validated for showing intercenter differences for overall bone fill as well as in vertical thirds. Surgical technique, timing, and expertise/volume were identified as possible factors related to outcome.

  18. Coriolis forces influence the secondary circulation of gravity currents flowing in large-scale sinuous submarine channel systems

    Science.gov (United States)

    Cossu, Remo; Wells, Mathew G.

    2010-09-01

    A combination of centrifugal and Coriolis forces drive the secondary circulation of turbidity currents in sinuous channels, and hence determine where erosion and deposition of sediment occur. Using laboratory experiments we show that when centrifugal forces dominate, the density interface shows a superelevation at the outside of a channel bend. However when Coriolis forces dominate, the interface is always deflected to the right (in the Northern Hemisphere) for both left and right turning bends. The relative importance of either centrifugal or Coriolis forces can be described in terms of a Rossby number defined as Ro = U/fR, where U is the mean downstream velocity, f the Coriolis parameter and R the radius of curvature of the channel bend. Channels with larger bends at high latitudes have ∣Ro∣ < 1 and are dominated by Coriolis forces, whereas smaller, tighter bends at low latitudes have ∣Ro∣ $\\gg$ 1 and are dominated by centrifugal forces.

  19. Coriolis forces influence the secondary circulation of gravity currents flowing in large scale sinuous submarine channel systems

    Science.gov (United States)

    Cossu, R.; Wells, M. G.

    2010-12-01

    A combination of centrifugal and Coriolis forces drive the secondary circulation of turbidity currents in sinuous channels, and hence determine where erosion and deposition of sediment occur. Using laboratory experiments we show that when centrifugal forces dominate, the density interface shows a superelevation at the outside of a channel bend. However when Coriolis forces dominate, the interface is always deflected to the right (in the Northern Hemisphere) for both left and right turning bends. The relative importance of either centrifugal or Coriolis forces can be described in terms of a Rossby number defined as Ro = U/fR, where U is the mean downstream velocity, f the Coriolis parameter and R the radius of curvature of the channel bend. Channels with larger bends at high latitudes have |Ro|>1 and are dominated by centrifugal forces.

  20. A secondary organic aerosol formation model considering successive oxidation aging and kinetic condensation of organic compounds: global scale implications

    Directory of Open Access Journals (Sweden)

    F. Yu

    2011-02-01

    Full Text Available The widely used two-product secondary organic aerosol (SOA formation model has been extended in this study to consider the volatility changes of secondary organic gases (SOG arising from the aging process as well as the kinetic condensation of low volatile SOG (LV-SOG. In addition to semi-volatile SOG (SV-SOG with saturation vapor pressure at 290 K (C*290 in the range of ~3 ppt–3 ppb and medium-volatile SOG (MV-SOG with C*290 in the range of ~0.3–300 ppb, we add a third component representing LV-SOG with C*290 below ~3 ppt and design a scheme to transfer MV-SOG to SV-SOG and SV-SOG to LV-SOG associated with oxidation aging. This extended SOA formation model has been implemented in a global aerosol model (GEOS-Chem and the co-condensation of H2SO4 and LV-SOG on pre-existing particles is explicitly simulated. We show that, over many parts of the continents, LV-SOG concentrations are generally a factor of ~2–20 higher than those of H2SO4 and the kinetic condensation of LV-SOG significantly enhances particle growth rates. Comparisons of the simulated and observed evolution of particle size distributions at a boreal forest site (Hyytiälä, Finland clearly show that LV-SOG condensation is critical in order to bring the simulations closer to the observations. With the new SOA formation scheme, annual mean SOA mass increases by a factor of 2–10 in many parts of the boundary layer and reaches above 0.5 μg m−3 in most parts of the main continents, improving the agreement with aerosol mass spectrometer (AMS SOA measurements. While the new scheme generally decreases the concentration of condensation nuclei larger than 10 nm by 3–30% in the lower boundary layer as a result of enhanced surface area and reduced nucleation rates, it substantially increases the concentration of cloud condensation nuclei at a

  1. Exergy and economic analysis of organic rankine cycle hybrid system utilizing biogas and solar energy in rural area of China

    DEFF Research Database (Denmark)

    Zhao, Chunhua; Zheng, Siyu; Zhang, Ji

    2017-01-01

    Due to the existing huge biogas resource in the rural area of China, biogas is widely used for production and living. Cogeneration system provides an opportunity to realize the balanced utilization of the renewable energy such as biogas and solar energy. This paper presented a numerical...... investigation of a hybrid energy-driven organic Rankine cycle (ORC) cogeneration system, involving a solar organic Rankine cycle and a biogas boiler. The biogas boiler with a module of solar Parabolic-Trough Collectors (PTC) is employed to provide heat source to the ORC via two distinct intermediate pressurized...... circuits. The cogeneration supplied the power to the air-condition in summer condition and hot water, which is heated in the condenser, in winter condition. The system performance under the subcritical pressures has been assessed according to the energy-exergy and economic analysis with the organic working...

  2. Radial turbine expander design for organic rankine cycle, waste heat recovery in high efficiency, off-highway vehicles

    OpenAIRE

    Alshammari, F.; Karvountzis-Kontakiotis, A; Pesiridis, A

    2016-01-01

    Although state-of-the-art, heavy duty diesel engines of today can reach peak thermal efficiencies of approximately 45%, still most of the fuel energy is transformed into wasted heat in the internal combustion process. Recovering this wasted energy could increase the overall thermal efficiency of the engine as well as reduce the exhaust gas emissions. Compared to other Waste Heat Recovery (WHR) technologies, Organic Rankine Cycle (ORC) systems are regarded favourably due to their relative simp...

  3. Part-Load Performance of a Wet Indirectly Fired Gas Turbine Integrated with an Organic Rankine Cycle Turbogenerator

    OpenAIRE

    Leonardo Pierobon; Tuong-Van Nguyen; Andrea Mazzucco; Ulrik Larsen; Fredrik Haglind

    2014-01-01

    Over the last years, much attention has been paid to the development of efficient and low-cost power systems for biomass-to-electricity conversion. This paper aims at investigating the design- and part-load performance of an innovative plant based on a wet indirectly fired gas turbine (WIFGT) fueled by woodchips and an organic Rankine cycle (ORC) turbogenerator. An exergy analysis is performed to identify the sources of inefficiencies, the optimal design variables, and the most suitable worki...

  4. Modelling of organic Rankine cycle power systems in off-design conditions: an experimentally-validated comparative study

    OpenAIRE

    Dickes, Rémi; Dumont, Olivier; Daccord, Rémi; Quoilin, Sylvain; Lemort, Vincent

    2017-01-01

    Because of environmental issues and the depletion of fossil fuels, the world energy sector is undergoing many changes toward increased sustainability. Among the many fields of research and development, power generation from low-grade heat sources is gaining interest and the organic Rankine cycle (ORC) is seen as one of the most promising technologies for such applications. In this paper, it is proposed to perform an experimentally-validated comparison of different modelling methods for the of...

  5. Bayesian Zero-Failure (BAZE) reliability demonstration testing procedure and its application to a Rankine dynamic radioisotope power conversion system

    Energy Technology Data Exchange (ETDEWEB)

    Martz, H.F. Jr.; Waller, R.A.

    1976-07-01

    A Bayesian Zero-Failure (BAZE) reliability demonstration testing procedure is developed. The procedure may be used to verify component failure rates associated with both real-time dependent and cycle-dependent chance failure mechanisms. A constant falure-rate model with a gamma prior distribution is assumed. The procedure is used to obtain sample test plans for components of a proposed Rankine power conversion system.

  6. Test results of an organic Rankine-cycle power module for a small community solar thermal power experiment

    Science.gov (United States)

    Clark, T. B.

    1985-01-01

    The organic Rankine-cycle (ORC) power conversion assembly was tested. Qualification testing of the electrical transport subsystem was also completed. Test objectives were to verify compatibility of all system elements with emphasis on control of the power conversion assembly, to evaluate the performance and efficiency of the components, and to validate operating procedures. After 34 hours of power generation under a wide range of conditions, the net module efficiency exceeded 18% after accounting for all parasitic losses.

  7. Performance of Siloxane Mixtures in a High-Temperature Organic Rankine Cycle Considering the Heat Transfer Characteristics during Evaporation

    OpenAIRE

    Theresa Weith; Florian Heberle; Markus Preißinger; Dieter Brüggemann

    2014-01-01

    The application of the Organic Rankine Cycle to high temperature heat sources is investigated on the case study of waste heat recovery from a selected biogas plant. Two different modes of operation are distinguished: pure electric power and combined heat and power generation. The siloxanes hexamethyldisiloxane (MM) and octamethyltrisiloxane (MDM) are chosen as working fluids. Moreover, the effect of using mixtures of these components is analysed. Regarding pure electricity generation, process...

  8. Organic Rankine cycle – review and research directions in engine applications

    Directory of Open Access Journals (Sweden)

    Panesar Angad

    2017-01-01

    Full Text Available Waste heat to power conversion using Organic Rankine Cycles (ORC is expected to play an important role in CO2 reductions from diesel engines. Firstly, a review of automotive ORCs is presented focusing on the pure working fluids, thermal architectures and expanders. The discussion includes, but is not limited to: R245fa, ethanol and water as fluids; series, parallel and cascade as architectures; dry saturated, superheated and supercritical as expansion conditions; and scroll, radial turbine and piston as expansion machines. Secondly, research direction in versatile expander and holistic architecture (NOx + CO2 are proposed. Benefits of using the proposed unconventional approaches are quantified using Ricardo Wave and Aspen HYSYS for diesel engine and ORC modelling. Results indicate that, the implementation of versatile piston expander tolerant to two-phase and using cyclopentane can potentially increase the highway drive cycle power by 8%. Furthermore, holistic architecture offering complete utilisation of charge air and exhaust recirculation heat increased the performance noticeably to 5% of engine power at the design point condition.

  9. Exergetic Analysis of an Integrated Tri-Generation Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Ratha Z. Mathkor

    2015-08-01

    Full Text Available This paper reports on a study of the modelling, validation and analysis of an integrated 1 MW (electrical output tri-generation system energized by solar energy. The impact of local climatic conditions in the Mediterranean region on the system performance was considered. The output of the system that comprised a parabolic trough collector (PTC, an organic Rankine cycle (ORC, single-effect desalination (SED, and single effect LiBr-H2O absorption chiller (ACH was electrical power, distilled water, and refrigerant load. The electrical power was produced by the ORC which used cyclopentane as working fluid and Therminol VP-1 was specified as the heat transfer oil (HTO in the collectors with thermal storage. The absorption chiller and the desalination unit were utilize the waste heat exiting from the steam turbine in the ORC to provide the necessary cooling energy and drinking water respectively. The modelling, which includes an exergetic analysis, focuses on the performance of the solar tri-generation system. The simulation results of the tri-generation system and its subsystems were produced using IPSEpro software and were validated against experimental data which showed good agreement. The tri-generation system was able to produce about 194 Ton of refrigeration, and 234 t/day distilled water.

  10. Organic Rankine kilowatt isotope power system. First annual summary report, August 1, 1975--August 1, 1976

    Energy Technology Data Exchange (ETDEWEB)

    1976-01-01

    Sundstrand Energy Systems is developing a Kilowatt Isotope Power System (KIPS) directed toward satisfying the higher power requirements of satellites of the 1980's. The KIPS is a plutonium oxide fueled organic Rankine cycle turbine power system which will provide design output power in the range of 500 to 2000 W(e) with a minimum of system changes. Research progress is reported on Phase I comprising: (1) flight system conceptual design and ground demonstration; (2) flight system design and ground qualification; and (3) flight system production, acceptance testing and delivery. The principal objectives of Phase I are to: (1) conceptually design the flight system, (2) based on the flight system concept, design and build the ground demonstration system (GDS), (3) conduct performance and endurance testing using electric heaters to simulate the radioisotope heat source, (4) identify and initiate long lead development efforts required to achieve the initial flight qualification hardware availability date of April 1981, and (5) finalize the flight concept design and prepare the program plan for the Phase II effort.

  11. Energy analysis of a trigeneration plant based on solid oxide fuel cell and organic Rankine cycle

    Energy Technology Data Exchange (ETDEWEB)

    Al-Sulaiman, Fahad A. [Mechanical and Aerospace Engineering Department, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario (Canada); Dincer, Ibrahim [Faculty of Engineering and Applied Science, University of Ontario Institute of Technology, 2000 Simcoe Street North, Oshawa, Ontario (Canada); Hamdullahpur, Feridun [Mechanical and Mechatronics Engineering Department, University of Waterloo, 200 University Avenue West, Waterloo, Ontario (Canada)

    2010-05-15

    In this study, energy analysis of a trigeneration plant based on solid oxide fuel cell (SOFC) and organic Rankine cycle (ORC) is conducted. The physical and thermodynamic elements of the plant include an SOFC, an ORC, a heat exchanger for the heating process and a single-effect absorption chiller for cooling. The results obtained from this study show that there is at least a 22% gain in efficiency using the trigeneration plant compared with the power cycle (SOFC and ORC). The study also shows that the maximum efficiency of the trigeneration plant is 74%, heating cogeneration is 71%, cooling cogeneration is 57% and net electricity is 46%. Furthermore, it is found that the highest net power output that can be provided by the trigeneration plant considered in this study is 540 kW and, the highest SOFC-AC power is 520 kW. The study reveals that the inlet pressure of the turbine has an insignificant effect on the efficiency. The study also examines the effect of both the SOFC current density and the SOFC inlet flow temperature on the cell voltage and voltage loss. (author)

  12. Numerical computation of motions and structural loads for large containership using 3D Rankine panel method

    Science.gov (United States)

    Kim, Jung-Hyun; Kim, Yonghwan

    2017-12-01

    In this paper, we present the results of our numerical seakeeping analyses of a 6750-TEU containership, which were subjected to the benchmark test of the 2nd ITTC-ISSC Joint Workshop held in 2014. We performed the seakeeping analyses using three different methods based on a 3D Rankine panel method, including 1) a rigid-body solver, 2) a flexible-body solver using a beam model, and 3) a flexible-body solver using the eigenvectors of a 3D Finite Element Model (FEM). The flexible-body solvers adopt a fully coupled approach between the fluid and structure. We consider the nonlinear Froude-Krylov and restoring forces using a weakly nonlinear approach. In addition, we calculate the slamming loads on the bow flare and stern using a 2D generalized Wagner model. We compare the numerical and experimental results in terms of the linear response, the time series of the nonlinear response, and the longitudinal distribution of the sagging and hogging moments. The flexible-body solvers show good agreement with the experimental model with respect to both the linear and nonlinear results, including the high-frequency oscillations due to springing and whipping vibrations. The rigid-body solver gives similar results except for the springing and whipping.

  13. Performance analysis of an organic Rankine cycle with internal heat exchanger having zeotropic working fluid

    Directory of Open Access Journals (Sweden)

    Thoranis Deethayat

    2015-09-01

    Full Text Available In this study, performance of a 50 kW organic Rankine cycle (ORC with internal heat exchanger (IHE having R245fa/R152a zeotropic refrigerant with various compositions was investigated. The IHE could reduce heat rate at the ORC evaporator and better cycle efficiency could be obtained. The zeotropic mixture could reduce the irreversibilities during the heat exchanges at the ORC evaporator and the ORC condenser due to its gliding temperature; thus the cycle working temperatures came closer to the temperatures of the heat source and the heat sink. In this paper, effects of evaporating temperature, mass fraction of R152a and effectiveness of internal heat exchanger on the ORC performances for the first law and the second law of thermodynamics were considered. The simulated results showed that reduction of R245fa composition could reduce the irreversibilities at the evaporator and the condenser. The suitable composition of R245fa was around 80% mass fraction and below this the irreversibilities were nearly steady. Higher evaporating temperature and higher internal heat exchanger effectiveness also increased the first law and second law efficiencies. A set of correlations to estimate the first and the second law efficiencies with the mass fraction of R245fa, the internal heat exchanger effectiveness and the evaporating temperature were also developed.

  14. Organic Rankine Cycle Analysis: Finding the Best Way to Utilize Waste Heat

    Directory of Open Access Journals (Sweden)

    Nadim Chakroun

    2012-01-01

    Full Text Available An Organic Rankine Cycle (ORC is a type of power cyclethat uses organic substances such as hydrocarbons orrefrigerants as the working fluid. ORC technology is usedto generate electricity in waste heat recovery applications,because the available heat is not at a high enoughtemperature to operate with other types of cycles. Theoptimum amount of working fluid required for the cycle(i.e., optimum charge level was investigated. Three chargelevels (13, 15, and 18 lbm were tested, and their effect onefficiency and performance of the system was analyzed.The heat source for the fluid was waste steam from thePurdue Power Plant, which had an average temperatureof 120oC. Regular city tap water at a temperature of 15oCwas used as the heat sink. For each charge level, multipletests were performed by measuring the temperaturesand pressures at all state points in the cycle, in order tounderstand any overarching patterns within the data.An important parameter that was analyzed is the 2nd lawefficiency. This efficiency is a measure of the effectivenessof the energy utilization compared to that of an idealcase. The peak efficiency increased from 24% to 27% asthe charge in the system decreased. Therefore, movingforward, this research suggests that a lower charge levelin the system will increase efficiency. However, testingbelow 13 lbm might cause mechanical complications inthe equipment as there may not be enough fluid to flowaround; thus, a compromise had to be made.

  15. Dynamic Simulation of an Organic Rankine Cycle—Detailed Model of a Kettle Boiler

    Directory of Open Access Journals (Sweden)

    Roberto Pili

    2017-04-01

    Full Text Available Organic Rankine Cycles (ORCs are nowadays a valuable technology to produce electricity from low and medium temperature heat sources, e.g., in geothermal, biomass and waste heat recovery applications. Dynamic simulations can help improve the flexibility and operation of such plants, and guarantee a better economic performance. In this work, a dynamic model for a multi-pass kettle evaporator of a geothermal ORC power plant has been developed and its dynamics have been validated against measured data. The model combines the finite volume approach on the tube side and a two-volume cavity on the shell side. To validate the dynamic model, a positive and a negative step function in heat source flow rate is applied. The simulation model performed well in both cases. The liquid level appeared the most challenging quantity to simulate. A better agreement in temperature was achieved by increasing the volume flow rate of the geothermal brine by 2% over the entire simulation. Measurement errors, discrepancies in working fluid and thermal brine properties and uncertainties in heat transfer correlations can account for this. In the future, the entire geothermal power plant will be simulated, and suggestions to improve its dynamics and control by means of simulations will be provided.

  16. Simulation of a passive house coupled with a heat pump/organic Rankine cycle reversible unit

    DEFF Research Database (Denmark)

    Dumont, Olivier; Carmo, Carolina; Randaxhe, François

    2014-01-01

    This paper presents a dynamic model of a passive house located in Denmark with a large solar absorber, a horizontal ground heat exchanger coupled with a HP/ORC unit. The HP/ORC reversible unit is a module able to work as an Organic Rankine Cycle (ORC) or as a heat pump (HP). There are 3 possible...... modes that need to be chosen optimally depending on the weather conditions, the heat demand and the temperature level of the storage. The ORC mode is activated, as long as the heat demand of the house is covered by the storage to produce electricity based upon the heat generated by the solar roof...... of the year in the Modelica language. A peak of 3.28 kW of power is reached in ORC mode with a heat input of 59.5 kW from the solar roof (23.9 kWh are produced during a typical summer day). In a representative winter day, 17.28 kWh are consumed by the heat pump with a daily average COP of 4.1. Conclusions...

  17. Comparison of different iterative schemes for ISPH based on Rankine source solution

    Directory of Open Access Journals (Sweden)

    Xing Zheng

    2017-07-01

    Full Text Available Smoothed Particle Hydrodynamics (SPH method has a good adaptability for the simulation of free surface flow problems. There are two forms of SPH. One is weak compressible SPH and the other one is incompressible SPH (ISPH. Compared with the former one, ISPH method performs better in many cases. ISPH based on Rankine source solution can perform better than traditional ISPH, as it can use larger stepping length by avoiding the second order derivative in pressure Poisson equation. However, ISPH_R method needs to solve the sparse linear matrix for pressure Poisson equation, which is one of the most expensive parts during one time stepping calculation. Iterative methods are normally used for solving Poisson equation with large particle numbers. However, there are many iterative methods available and the question for using which one is still open. In this paper, three iterative methods, CGS, Bi-CGstab and GMRES are compared, which are suitable and typical for large unsymmetrical sparse matrix solutions. According to the numerical tests on different cases, still water test, dam breaking, violent tank sloshing, solitary wave slamming, the GMRES method is more efficient than CGS and Bi-CGstab for ISPH method.

  18. Organic Rankine-cycle power systems working fluids study: Topical report No. 2, Toluene

    Energy Technology Data Exchange (ETDEWEB)

    Cole, R.L.; Demirgian, J.C.; Allen, J.W.

    1987-02-01

    The US Department of Energy initiated an investigation at Argonne National Laboratory in 1982 to experimentally determine the thermal stability limits and degradation rates of toluene as a function of maximum cycle temperature. Following the design and construction of a dynamic test loop capable of closely simulating the thermodynamic conditions of typical organic Rankine-cycle (ORC) power systems, four test runs, totaling about 3900 h of test time and covering a temperature range of 600-677(degree)F, were completed. Both liquid and noncondensable-vapor (gaseous) samples were drawn periodically and analyzed using capillary-column gas chromatography, gas chromatography/mass spectrometry, and mass spectrometry. A computer program that can predict degradation in an ORC engine was developed. Experimental results indicate that, if oxygen can be excluded from the system, toluene is a stable fluid up to the maximum test temperature; the charge of toluene could be used for several years before replacement became necessary. (Additional data provided by Sundstrand Corp. from tests sponsored by the National Aeronautics and Space Administration indicate that toluene may be used at temperatures up to 750(degree)F.) Degradation products are benign; the main liquid degradation products are bibenzyls, and the main gaseous degradation products are hydrogen and methane. A cold trap to remove gaseous degradation products from the condenser is necessary for extended operation. 21 figs., 22 tabs.

  19. Corrections to the Rankine-Hugoniot conditions for curved shock waves

    Science.gov (United States)

    Lancellotti, Carlo; Yue, Yubei

    2014-12-01

    Several years ago, Carlo Cercignani and one of the authors in a paper (C. Cercignani, 2991) performed a mathe-matical analysis of the corrections to the Rankine-Hugoniot conditions due to the curvature of a shock front, using singular perturbation methods in order to "connect" the solutions to the the Boltzmann equation inside and outside the shock layer. It turned out that these corrections can be obtained at leading order by integrating appropriately the Boltzmann shock profile for a planar (one-dimensional in space) shock wave. However, they are entirely due to the spatially asymmetry of the shock, and they vanish if the shock is described using a simple bi-modal ansatz like the well-know Mott-Smith model. In the present work we extend and simplify the previous results, and then use a recently-developed deterministic (spectral) Boltzmann solver for a gas of hard-spheres in order to obtain accurate numerical values for the curvature corrections.

  20. Thermal analysis of a Phase Change Material for a Solar Organic Rankine Cycle

    Science.gov (United States)

    Iasiello, M.; Braimakis, K.; Andreozzi, A.; Karellas, S.

    2017-11-01

    Organic Rankine Cycle (ORC) is a promising technology for low temperature power generation, for example for the utilization of medium temperature solar energy. Since heat generated from solar source is variable throughout the day, the implementation of Thermal Energy Storage (TES) systems to guarantee the continuous operation of solar ORCs is a critical task, and Phase Change Materials (PCM) rely on latent heat to store large amounts of energy. In the present study, a thermal analysis of a PCM for a solar ORC is carried out. Three different types of PCMs are analyzed. The energy equation for the PCM is modeled by using the heat capacity method, and it is solved by employing a 1Dexplicit finite difference scheme. The solar source is modeled with a time-variable temperature boundary condition, with experimental data taken from the literature for two different solar collectors. Results are presented in terms of temperature profiles and stored energy. It has been shown that the stored energy depends on the heat source temperature, on the employed PCM and on the boundary conditions. It has been demonstrated that the use of a metal foam can drastically enhance the stored energy due to the higher overall thermal conductivity.

  1. The simulation of organic rankine cycle power plant with n-pentane working fluid

    Science.gov (United States)

    Nurhilal, Otong; Mulyana, Cukup; Suhendi, Nendi; Sapdiana, Didi

    2016-02-01

    In the steam power plant in Indonesia the dry steam from separator directly used to drive the turbin. Meanwhile, brine from the separator with low grade temperature reinjected to the earth. The brine with low grade temperature can be converted indirectly to electrical power by organic Rankine cycle (ORC) methods. In ORC power plant the steam are released from vaporization of organic working fluid by brine. The steam released are used to drive an turbine which in connected to generator to convert the mechanical energy into electric energy. The objective of this research is the simulation ORC power plant with n-pentane as organic working fluid. The result of the simulation for brine temperature around 165°C and the pressure 8.001 bar optained the net electric power around 1173 kW with the cycle thermal efficiency 14.61% and the flow rate of n-pentane around 15.51 kg/s. This result enable to applied in any geothermal source in Indonesia.

  2. Thermo-Economic Evaluation of Organic Rankine Cycles for Geothermal Power Generation Using Zeotropic Mixtures

    Directory of Open Access Journals (Sweden)

    Florian Heberle

    2015-03-01

    Full Text Available We present a thermo-economic evaluation of binary power plants based on the Organic Rankine Cycle (ORC for geothermal power generation. The focus of this study is to analyse if an efficiency increase by using zeotropic mixtures as working fluid overcompensates additional requirements regarding the major power plant components. The optimization approach is compared to systems with pure media. Based on process simulations, heat exchange equipment is designed and cost estimations are performed. For heat source temperatures between 100 and 180 °C selected zeotropic mixtures lead to an increase in second law efficiency of up to 20.6% compared to pure fluids. Especially for temperatures about 160 °C, mixtures like propane/isobutane, isobutane/isopentane, or R227ea/R245fa show lower electricity generation costs compared to the most efficient pure fluid. In case of a geothermal fluid temperature of 120 °C, R227ea and propane/isobutane are cost-efficient working fluids. The uncertainties regarding fluid properties of zeotropic mixtures, mainly affect the heat exchange surface. However, the influence on the determined economic parameter is marginal. In general, zeotropic mixtures are a promising approach to improve the economics of geothermal ORC systems. Additionally, the use of mixtures increases the spectrum of potential working fluids, which is important in context of present and future legal requirements considering fluorinated refrigerants.

  3. Reciprocating Expander for an Exhaust Heat Recovery Rankine Cycle for a Passenger Car Application

    Directory of Open Access Journals (Sweden)

    Osoko Shonda

    2012-06-01

    Full Text Available Nowadays, on average, two thirds of the fuel energy consumed by an engine is wasted through the exhaust gases and the cooling liquid. The recovery of this energy would enable a substantial reduction in fuel consumption. One solution is to integrate a heat recovery system based on a steam Rankine cycle. The key component in such a system is the expander, which has a strong impact on the system’s performance. A survey of different expander technologies leads us to select the reciprocating expander as the most promising one for an automotive application. This paper therefore proposes a steady-state semi-empirical model of the expander device developed under the Engineering Equation Solver (EES environment. The ambient and mechanical losses as well as internal leakage were taken into account by the model. By exploiting the expander manufacturer’s data, all the parameters of the expander model were identified. The model computes the mass flow rate, the power output delivered and the exhaust enthalpy of the steam. The maximum deviation between predictions and measurement data is 4.7%. A performance study of the expander is carried out and shows that the isentropic efficiency is quite high and increases with the expander rotary speed. The mechanical efficiency depends on mechanical losses which are quite high, approximately 90%. The volumetric efficiency was also evaluated.

  4. Evaluation of a solar-powered organic Rankine cycle using dry organic working fluids

    Directory of Open Access Journals (Sweden)

    Emily Spayde

    2015-12-01

    Full Text Available This paper presents a model to evaluate the performance of a solar-powered organic Rankine cycle (ORC. The system was evaluated in Jackson, MS, using five dry organic working fluids, R218, R227ea, R236ea, R236fa, and RC318. The purpose of this study is to investigate how hourly temperature change affects the electricity production and exergy destruction rates of the solar ORC, and to determine the effect of the working fluid on the proposed system. The system was also evaluated in Tucson, AZ, to investigate the effect of average hourly outdoor temperatures on its performance. The potential of the system to reduce primary energy consumption and carbon dioxide emissions is also investigated. A parametric analysis to determine how temperature and pressure of the organic working fluid, the solar collector area, and the turbine efficiency affect the electricity production is performed. Results show that the ORC produces the most electricity during the middle of the day, when the temperatures are the highest and when the solar collectors have the highest efficiency. Also, R-236ea is the working fluid that shows the best performance of the evaluated fluids. An economic analysis was performed to determine the capital cost available for the proposed system.

  5. Dual-objective optimization of organic Rankine cycle (ORC) systems using genetic algorithm: a comparison between basic and recuperative cycles

    Science.gov (United States)

    Hayat, Nasir; Ameen, Muhammad Tahir; Tariq, Muhammad Kashif; Shah, Syed Nadeem Abbas; Naveed, Ahmad

    2017-08-01

    Exploitation of low potential waste thermal energy for useful net power output can be done by manipulating organic Rankine cycle systems. In the current article dual-objectives (η_{th} and SIC) optimization of ORC systems [basic organic Rankine cycle (BORC) and recuperative organic Rankine cycle (RORC)] has been done using non-dominated sorting genetic algorithm (II). Seven organic compounds (R-123, R-1234ze, R-152a, R-21, R-236ea, R-245ca and R-601) have been employed in basic cycle and four dry compounds (R-123, R-236ea, R-245ca and R-601) have been employed in recuperative cycle to investigate the behaviour of two systems and compare their performance. Sensitivity analyses show that recuperation boosts the thermodynamic behaviour of systems but it also raises specific investment cost significantly. R-21, R-245ca and R-601 show attractive performance in BORC whereas R-601 and R-236ea in RORC. RORC, due to higher total investment cost and operation & maintenance costs, has longer payback periods as compared to BORC.

  6. Part-Load Performance of aWet Indirectly Fired Gas Turbine Integrated with an Organic Rankine Cycle Turbogenerator

    Directory of Open Access Journals (Sweden)

    Leonardo Pierobon

    2014-12-01

    Full Text Available Over the last years, much attention has been paid to the development of efficient and low-cost power systems for biomass-to-electricity conversion. This paper aims at investigating the design- and part-load performance of an innovative plant based on a wet indirectly fired gas turbine (WIFGT fueled by woodchips and an organic Rankine cycle (ORC turbogenerator. An exergy analysis is performed to identify the sources of inefficiencies, the optimal design variables, and the most suitable working fluid for the organic Rankine process. This step enables to parametrize the part-load model of the plant and to estimate its performance at different power outputs. The novel plant has a nominal power of 250 kW and a thermal efficiency of 43%. The major irreversibilities take place in the burner, recuperator, compressor and in the condenser. Toluene is the optimal working fluid for the organic Rankine engine. The part-load investigation indicates that the plant can operate at high efficiencies over a wide range of power outputs (50%–100%, with a peak thermal efficiency of 45% at around 80% load. While the ORC turbogenerator is responsible for the efficiency drop at low capacities, the off-design performance is governed by the efficiency characteristics of the compressor and turbine serving the gas turbine unit.

  7. A Comparative Exergoeconomic Analysis of Waste Heat Recovery from a Gas Turbine-Modular Helium Reactor via Organic Rankine Cycles

    Directory of Open Access Journals (Sweden)

    Naser Shokati

    2014-04-01

    Full Text Available A comparative exergoeconomic analysis is reported for waste heat recovery from a gas turbine-modular helium reactor (GT-MHR using various configurations of organic Rankine cycles (ORCs for generating electricity. The ORC configurations studied are: a simple organic Rankine cycle (SORC, an ORC with an internal heat exchanger (HORC and a regenerative organic Rankine cycle (RORC. Exergoeconomic analyses are performed with the specific exergy costing (SPECO method. First, energy and exergy analyses are applied to the combined cycles. Then, a cost-balance, as well as auxiliary equations are developed for the components to determine the exergoeconomic parameters for the combined cycles and their components. The three combined cycles are compared considering the same operating conditions for the GT-MHR cycle, and a parametric study is done to reveal the effects on the exergoeconomic performance of the combined cycles of various significant parameters, e.g., turbine inlet and evaporator temperatures and compressor pressure ratio. The results show that the GT-MHR/RORC has the lowest unit cost of electricity generated by the ORC turbine. This value is highest for the GT-MHR/HORC. Furthermore, the GT-MHR/RORC has the highest and the GT-MHR/HORC has the lowest exergy destruction cost rate.

  8. Effect of Regenerative Organic Rankine Cycle (RORC on the Performance of Solar Thermal Power in Yogyakarta, Indonesia

    Directory of Open Access Journals (Sweden)

    Ghalya Pikra

    2013-07-01

    Full Text Available This paper presents effect of Regenerative Organic Rankine Cycle (RORC on the performance of solar thermal power in Yogyakarta, Indonesia. Solar thermal power is a plant that uses solar energy as heat source. Indonesia has high humidity level, so that parabolic trough is the most suitable type of solar thermal power technology to be developed, where the design is made with small focal distance. Organic Rankine Cycle (ORC is a Rankine cycle that use organic fluid as working fluid to utilize low temperature heat sources. RORC is used to increase ORC performance. The analysis was done by comparing ORC system with and without regenerator addition. Refrigerant that be used in the analysis is R123. Preliminary data was taken from the solar collector system that has been installed in Yogyakarta. The analysis shows that with 36 m total parabolic length, the resulting solar collector capacity is 63 kW, heat input/evaporator capacity is determined 26.78 kW and turbine power is 3.11 kW for ORC, and 3.38 kW for RORC. ORC thermal efficiency is 11.28% and RORC is 12.26%. Overall electricity efficiency is 4.93% for ORC, and 5.36% for RORC. With 40°C condensing temperature and evaporation at 10 bar saturated condition, efficiency of RORC is higher than ORC. Greater evaporation temperature at the same pressure (10 bar provide greater turbine power and efficiency.

  9. Performance of a reversible heat pump/organic Rankine cycle unit coupled with a passive house to get a positive energy building

    DEFF Research Database (Denmark)

    Dumont, Olivier; Carmo, Carolina; Fontaine, Valentin

    2016-01-01

    and generate electricity, coupled to a solar thermal collector roof. This reversible HP/organic Rankine cycle unit presents three operating modes: direct heating, HP and organic Rankine cycle. This work focuses on describing the dynamic model of the multi-component system followed by a techno-economic analysis......Wh/year and total electrical consumption of 2318 kWh/year) with a 138.8 m2 solar roof in Denmark....

  10. A synthetic biological secondary metabolite, Lycogen™, produced and extracted from Rhodobacter sphaeroides WL-APD911 in an optimizatioal scale-up strategy

    Directory of Open Access Journals (Sweden)

    Cheng-Chin Wang

    2017-12-01

    Full Text Available The optimization of fermentation medium is important for synthetic biological secondary metabolite productions. The effect of rotation speed, inoculum amount, and medium supplements on the cell growth and Lycogen™ secretion of photobacterium Rhodobacter sphaeroides WL-APD911 was evaluated. The results reveal that a higher rotational speed exhibit a higher cell density, and the increasing in the amount of inoculum amount show a slight augment on the growth of R. sphaeroides WL-APD911.In the case of nitrogen sources adding, Lycogen™ production was achieved with a 0.5 mM l-lysine supplementation. Moreover, the attention of Tween 80 presented a tremendous increase in the secondary metabolite. Response surface methodology (RSM exhibited the optimization of medium supplements for Lycogen™ invention is accomplished at molasses concentration of 10 g/L, yeast extract concentration of 40 g/L, 0.3% Tween 80 and NaCl concentration of 5 g/L, respectively. Further, the batch fermentation is carried out in both 5 L and 20 L fermentors to study the scale-up process factors to be adopted. At a 20 L fermentor, Lycogen™ yields under the optimal culture condition are over 2 times than in the shake flask. The present results provide the Lycogen™ optimal culture mediums, scale-up procedures and efficient extractions from R. sphaeroides WL-APD911. Keywords: Rhodobacter sphaeroides WL-APD911, Lycogen™, Response surface methodology (RSM, Ferementation

  11. Alkali Metal Rankine Cycle Boiler Technology Challenges and Some Potential Solutions for Space Nuclear Power and Propulsion Applications

    Science.gov (United States)

    Stone, James R.

    1994-01-01

    Alkali metal boilers are of interest for application to future space Rankine cycle power conversion systems. Significant progress on such boilers was accomplished in the 1960's and early 1970's, but development was not continued to operational systems since NASA's plans for future space missions were drastically curtailed in the early 1970's. In particular, piloted Mars missions were indefinitely deferred. With the announcement of the Space Exploration Initiative (SEI) in July 1989 by President Bush, interest was rekindled in challenging space missions and, consequently in space nuclear power and propulsion. Nuclear electric propulsion (NEP) and nuclear thermal propulsion (NTP) were proposed for interplanetary space vehicles, particularly for Mars missions. The potassium Rankine power conversion cycle became of interest to provide electric power for NEP vehicles and for 'dual-mode' NTP vehicles, where the same reactor could be used directly for propulsion and (with an additional coolant loop) for power. Although the boiler is not a major contributor to system mass, it is of critical importance because of its interaction with the rest of the power conversion system; it can cause problems for other components such as excess liquid droplets entering the turbine, thereby reducing its life, or more critically, it can drive instabilities-some severe enough to cause system failure. Funding for the SEI and its associated technology program from 1990 to 1993 was not sufficient to support significant new work on Rankine cycle boilers for space applications. In Fiscal Year 1994, funding for these challenging missions and technologies has again been curtailed, and planning for the future is very uncertain. The purpose of this paper is to review the technologies developed in the 1960's and 1970's in the light of the recent SEI applications. In this way, future Rankine cycle boiler programs may be conducted most efficiently. This report is aimed at evaluating alkali metal boiler

  12. Development and a Validation of a Charge Sensitive Organic Rankine Cycle (ORC Simulation Tool

    Directory of Open Access Journals (Sweden)

    Davide Ziviani

    2016-05-01

    Full Text Available Despite the increasing interest in organic Rankine cycle (ORC systems and the large number of cycle models proposed in the literature, charge-based ORC models are still almost absent. In this paper, a detailed overall ORC simulation model is presented based on two solution strategies: condenser subcooling and total working fluid charge of the system. The latter allows the subcooling level to be predicted rather than specified as an input. The overall cycle model is composed of independent models for pump, expander, line sets, liquid receiver and heat exchangers. Empirical and semi-empirical models are adopted for the pump and expander, respectively. A generalized steady-state moving boundary method is used to model the heat exchangers. The line sets and liquid receiver are used to better estimate the total charge of the system and pressure drops. Finally, the individual components are connected to form a cycle model in an object-oriented fashion. The solution algorithm includes a preconditioner to guess reasonable values for the evaporating and condensing temperatures and a main cycle solver loop which drives to zero a set of residuals to ensure the convergence of the solution. The model has been developed in the Python programming language. A thorough validation is then carried out against experimental data obtained from two test setups having different nominal size, working fluids and individual components: (i a regenerative ORC with a 5 kW scroll expander and an oil flooding loop; (ii a regenerative ORC with a 11 kW single-screw expander. The computer code is made available through open-source dissemination.

  13. Stand-Alone Solar Organic Rankine Cycle Water Pumping System and Its Economic Viability in Nepal

    Directory of Open Access Journals (Sweden)

    Suresh Baral

    2015-12-01

    Full Text Available The current study presents the concept of a stand-alone solar organic Rankine cycle (ORC water pumping system for rural Nepalese areas. Experimental results for this technology are presented based on a prototype. The economic viability of the system was assessed based on solar radiation data of different Nepalese geographic locations. The mechanical power produced by the solar ORC is coupled with a water pumping system for various applications, such as drinking and irrigation. The thermal efficiency of the system was found to be 8% with an operating temperature of 120 °C. The hot water produced by the unit has a temperature of 40 °C. Economic assessment was done for 1-kW and 5-kW solar ORC water pumping systems. These systems use different types of solar collectors: a parabolic trough collector (PTC and an evacuated tube collector (ETC. The economic analysis showed that the costs of water are $2.47/m3 (highest and $1.86/m3 (lowest for the 1-kW system and a 150-m pumping head. In addition, the cost of water is reduced when the size of the system is increased and the pumping head is reduced. The minimum volumes of water pumped are 2190 m3 and 11,100 m3 yearly for 1 kW and 5 kW, respectively. The payback period is eight years with a profitability index of 1.6. The system is highly feasible and promising in the context of Nepal.

  14. Thermo-Economic Performance Analysis of a Regenerative Superheating Organic Rankine Cycle for Waste Heat Recovery

    Directory of Open Access Journals (Sweden)

    Zhonghe Han

    2017-10-01

    Full Text Available The Organic Rankine Cycle (ORC is a promising form of technology for recovering low-grade waste heat. In this study, a regenerative ORC system is established to recover the waste flue gas of 160 °C. Focusing on thermodynamic and economic performance while simultaneously considering the limitations of volume flow ratio (VFR and the effect of superheat, working fluid selection and parameter optimization have been investigated. The optimization of the evaporation temperature is carried out by analyzing the variation of net power output and specific investment cost (SIC. Then, the net power output, specific net power output, total exergy destruction rate, VFR, total capital cost, and levelized electricity cost (LEC are selected as criteria, and a fuzzy multi-criteria evaluation method is adopted to select a more suitable working fluid and determine the optimal degree of superheat. In addition, the preheating coefficient, latent heat coefficient, superheating coefficient, and internal heat coefficient were proposed to explore the effect of working fluid critical temperature on thermal efficiency. Research studies demonstrate that there is an optimal evaporation temperature, maximizing net power output and minimizing the SIC. Isohexane and butane have greater specific net power output due to greater latent heat. A suitable degree of superheat is not only conducive to improving the working capacity of working fluids, but also reduces the VFR, total capital cost, SIC, and LEC for different working fluids. Thus, the system’s thermodynamic and economic performance—as well as the operational stability—are improved. Among the six working fluids, butane exhibits the best comprehensive performance, and its optimal evaporation temperature and degree of superheat are 100 °C and 5 °C, respectively.

  15. Applied studies in advanced boiler technology for Rankine cycle power systems

    Energy Technology Data Exchange (ETDEWEB)

    Paul, F.W.; Negreanu, M.J.

    1978-02-01

    A study is presented on a new rotational boiler design which has improved passive dynamic response and two-phase flow stability characteristics. A survey of small boiler manufacturers in the United States indicated that currently available designs are based on steady-state operating requirements rather than for dynamic performance. Recent work by EPA and ERDA which addressed boiler designs for mobile automotive Rankine cycle power systems showed that boilers of a monotube or multipass tube configuration design could be developed which were physically compact, but still were subject to the two-phase flow instability problem when coupled within an operating power system. The objectives of this work were to evaluate alternative boiler configurations which would improve boiler dynamic response and also have good two-phase liquid-vapor interface flow stability. The major physical design limitation of any boiler is the small external hot gas heat transfer coefficient. Such a low coefficient requires considerable design enhancements to increase the rate of energy transfer to the circulation system fluid. The rotational boiler is a physical design configuration which addresses this problem. The results of an analytic study using several mathematical model formulations showed that a rotational boiler could have a passive response time constant which was approximately one-half the magnitude for an equivalent single pass monotube boiler. An experimental prototype rotational boiler was designed, manufactured and tested, with the experimental results confirming that the experimental passive response time constants were comparable to the estimates from the analytic models. The experimental boiler operating in two-phase flow was found to be stable and responsive to external inputs. A rotational boiler configuration is a good alternative design configuration for small compact vapor generator designs based on fast transient passive response and two-phase flow stability.

  16. Thermodynamic Optimization of a Geothermal- Based Organic Rankine Cycle System Using an Artificial Bee Colony Algorithm

    Directory of Open Access Journals (Sweden)

    Osman Özkaraca

    2017-10-01

    Full Text Available Geothermal energy is a renewable form of energy, however due to misuse, processing and management issues, it is necessary to use the resource more efficiently. To increase energy efficiency, energy systems engineers carry out careful energy control studies and offer alternative solutions. With this aim, this study was conducted to improve the performance of a real operating air-cooled organic Rankine cycle binary geothermal power plant (GPP and its components in the aspects of thermodynamic modeling, exergy analysis and optimization processes. In-depth information is obtained about the exergy (maximum work a system can make, exergy losses and destruction at the power plant and its components. Thus the performance of the power plant may be predicted with reasonable accuracy and better understanding is gained for the physical process to be used in improving the performance of the power plant. The results of the exergy analysis show that total exergy production rate and exergy efficiency of the GPP are 21 MW and 14.52%, respectively, after removing parasitic loads. The highest amount of exergy destruction occurs, respectively, in condenser 2, vaporizer HH2, condenser 1, pumps 1 and 2 as components requiring priority performance improvement. To maximize the system exergy efficiency, the artificial bee colony (ABC is applied to the model that simulates the actual GPP. Under all the optimization conditions, the maximum exergy efficiency for the GPP and its components is obtained. Two of these conditions such as Case 4 related to the turbine and Case 12 related to the condenser have the best performance. As a result, the ABC optimization method provides better quality information than exergy analysis. Based on the guidance of this study, the performance of power plants based on geothermal energy and other energy resources may be improved.

  17. Organic Rankine-Cycle Power Systems Working Fluids Study: Topical report No. 3, 2-methylpyridine/water

    Energy Technology Data Exchange (ETDEWEB)

    Cole, R.L.; Demirgian, J.C.; Allen, J.W.

    1987-09-01

    A mixture of 35 mole percent (mol %) 2-methylpyridine and 65 mol % water was tested at 575, 625, and 675/degree/F in a dynamic loop. Samples of the degraded fluid were chemically analyzed to determine the identities of major degradation products and the quantity of degradation. Computed degradation rates were found to be higher than those for Fluorinol 85 or toluene. For this reason (and other reasons, related to fluid handling), other fluids are recommended as the first choice for service in organic Rankine-cycle systems in preference to 2-methylpyridine/water. 7 refs., 39 figs., 39 tabs.

  18. Integrated working fluid-thermodynamic cycle design of organic Rankine cycle power systems for waste heat recovery

    DEFF Research Database (Denmark)

    Cignitti, Stefano; Andreasen, Jesper Graa; Haglind, Fredrik

    2017-01-01

    recovery. Inthis paper, an organic Rankine cycle process and its pure working fluid are designed simultaneously forwaste heat recovery of the exhaust gas from a marine diesel engine. This approach can overcome designissues caused by the high sensitivity between the fluid and cycle design variables...... the simultaneousdesign approach the optimum solution was found in 5.04 s, while a decomposed approach found thesame solution in 5.77 h. However, the decomposed approach provided insights on the correlationbetween the fluid and cycle design variables by analyzing all possible solutions. It was shown that thehigh...

  19. Design and development of an automotive propulsion system utilizing a Rankine cycle engine (water based fluid). Final report

    Energy Technology Data Exchange (ETDEWEB)

    Demler, R.L.

    1977-09-01

    Under EPA and ERDA sponsorship, SES successfully designed, fabricated and tested the first federally sponsored steam powered automobile. The automobile - referred to as the simulator - is a 1975 Dodge Monaco standard size passenger car with the SES preprototype Rankine cycle automotive propulsion system mounted in the engine compartment. In the latter half of 1975, the simulator successfully underwent test operations at the facilities of SES in Watertown, Massachusetts and demonstrated emission levels below those of the stringent federally established automotive requirements originally set for implementation by 1976. The demonstration was accomplished during testing over the Federal Driving Cycle on a Clayton chassis dynamometer. The design and performance of the vehicle are described.

  20. Experimental and thermodynamic analysis of a bottoming Organic Rankine Cycle (ORC) of gasoline engine using swash-plate expander

    OpenAIRE

    Galindo, José,; Ruiz Rosales, Santiago; Dolz Ruiz, Vicente; ROYO PASCUAL, LUCÍA; Haller, R.; Nicolas, B.; Glavatskaya, Y.

    2015-01-01

    This paper deals with the experimental testing of an Organic Rankine Cycle (ORC) integrate in a 2 liter turbocharged gasoline engine using ethanol as working fluid. The main components of the cycle are a boiler, a condenser, a pump and a swash-plate expander. Five engine operating points have been tested, they correspond to a nominal heat input into the boiler of 5, 12, 20, 25 and 30 kW. With the available bill of material based on prototypes, power balances and cycles efficiencies were estim...

  1. Development of an Organic Rankine-Cycle power module for a small community solar thermal power experiment

    Science.gov (United States)

    Kiceniuk, T.

    1985-01-01

    An organic Rankine-cycle (ORC) power module was developed for use in a multimodule solar power plant to be built and operated in a small community. Many successful components and subsystems, including the reciever, power conversion subsystem, energy transport subsystem, and control subsystem, were tested. Tests were performed on a complete power module using a test bed concentrator in place of the proposed concentrator. All major single-module program functional objectives were met and the multimodule operation presented no apparent problems. The hermetically sealed, self-contained, ORC power conversion unit subsequently successfully completed a 300-hour endurance run with no evidence of wear or operating problems.

  2. Factors influencing outcome in acute ischaemic stroke : outcome scales, the role of blood glucose and rtPA treatment

    NARCIS (Netherlands)

    Uyttenboogaart, Maarten

    2008-01-01

    This thesis describes several aspects that influence outcome in acute ischaemic strok. In the first part, two frequently used outcome scales - the Barthel index and modified Rankin scale - are studied and for both scales, optimal endpoints for stroke trials are proposed. In the second part, the

  3. Thermal energy storage for low grade heat in the organic Rankine cycle

    Science.gov (United States)

    Soda, Michael John

    Limits of efficiencies cause immense amounts of thermal energy in the form of waste heat to be vented to the atmosphere. Up to 60% of unrecovered waste heat is classified as low or ultra-low quality, making recovery difficult or inefficient. The organic Rankine cycle can be used to generate mechanical power and electricity from these low temperatures where other thermal cycles are impractical. A variety of organic working fluids are available to optimize the ORC for any target temperature range. San Diego State University has one such experimental ORC using R245fa, and has been experimenting with multiple expanders. One limitation of recovering waste heat is the sporadic or cyclical nature common to its production. This inconsistency makes sizing heat recovery ORC systems difficult for a variety of reasons including off-design-point efficiency loss, increased attrition from varying loads, unreliable outputs, and overall system costs. Thermal energy storage systems can address all of these issues by smoothing the thermal input to a constant and reliable level and providing back-up capacity for times when the thermal input is deactivated. Multiple types of thermal energy storage have been explored including sensible, latent, and thermochemical. Latent heat storage involves storing thermal energy in the reversible phase change of a phase change material, or PCM, and can have several advantages over other modalities including energy storage density, cost, simplicity, reliability, relatively constant temperature output, and temperature customizability. The largest obstacles to using latent heat storage include heat transfer rates, thermal cycling stability, and potentially corrosive PCMs. Targeting 86°C, the operating temperature of SDSU's experimental ORC, multiple potential materials were explored and tested as potential PCMs including Magnesium Chloride Hexahydrate (MgCl2˙6H2O), Magnesium Nitrate Hexahydrate (Mg(NO3)2˙6H 2O), montan wax, and carnauba wax. The

  4. A Burst Mode, Ultrahigh Temperature UF4 Vapor Core Reactor Rankine Cycle Space Power System Concept

    Science.gov (United States)

    Dugan, E. T.; Kahook, S. D.; Diaz, N. J.

    1996-01-01

    Static and dynamic neutronic analyses have been performed on an innovative burst mode (100's of MW output for a few thousand seconds) Ulvahigh Temperature Vapor Core Reactor (UTVR) space nuclear power system. The NVTR employs multiple, neutronically-coupled fissioning cores and operates on a direct, closed Rankine cycle using a disk Magnetohydrodynamic (MHD) generater for energy conversion. The UTVR includes two types of fissioning core regions: (1) the central Ultrahigh Temperature Vapor Core (UTVC) which contains a vapor mixture of highly enriched UF4 fuel and a metal fluoride working fluid and (2) the UF4 boiler column cores located in the BeO moderator/reflector region. The gaseous nature of the fuel the fact that the fuel is circulating, the multiple coupled fissioning cores, and the use of a two phase fissioning fuel lead to unique static and dynamic neutronic characteristics. Static neutronic analysis was conducted using two-dimensional S sub n, transport theory calculations and three-dimensional Monte Carlo transport theory calculations. Circulating-fuel, coupled-core point reactor kinetics equations were used for analyzing the dynamic behavior of the UTVR. In addition to including reactivity feedback phenomena associated with the individual fissioning cores, the effects of core-to-core neutronic and mass flow coupling between the UTVC and the surrounding boiler cores were also included in the dynamic model The dynamic analysis of the UTVR reveals the existence of some very effectlve inherent reactivity feedback effects that are capable of quickly stabilizing this system, within a few seconds, even when large positive reactivity insertions are imposed. If the UTVC vapor fuel density feedback is suppressed, the UTVR is still inherently stable because of the boiler core liquid-fuel volume feedback; in contrast, suppression of the vapor fuel density feedback in 'conventional" gas core cavity reactors causes them to become inherently unstable. Due to the

  5. The dish-Rankine SCSTPE program (Engineering Experiment no. 1). [systems engineering and economic analysis for a small community solar thermal electric system

    Science.gov (United States)

    Pons, R. L.; Grigsby, C. E.

    1980-01-01

    Activities planned for phase 2 Of the Small Community Solar Thermal Power Experiment (PFDR) program are summarized with emphasis on a dish-Rankine point focusing distributed receiver solar thermal electric system. Major design efforts include: (1) development of an advanced concept indirect-heated receiver;(2) development of hardware and software for a totally unmanned power plant control system; (3) implementation of a hybrid digital simulator which will validate plant operation prior to field testing; and (4) the acquisition of an efficient organic Rankine cycle power conversion unit. Preliminary performance analyses indicate that a mass-produced dish-Rankine PFDR system is potentially capable of producing electricity at a levelized busbar energy cost of 60 to 70 mills per KWh and with a capital cost of about $1300 per KW.

  6. An experimental analysis of flow boiling and pressure drop in a brazed plate heat exchanger for organic Rankine cycle power systems

    DEFF Research Database (Denmark)

    Desideri, Adriano; Zhang, Ji; Kærn, Martin Ryhl

    2017-01-01

    Organic Rankine cycle power systems for low quality waste heat recovery applications can play a major role in achieving targets of increasing industrial processes efficiency and thus reducing the emissions of greenhouse gases. Low capacity organic Rankine cycle systems are equipped with brazed...... and pressure drop during vaporization at typical temperatures for low quality waste heat recovery organic Rankine cycle systems are presented for the working fluids HFC-245fa and HFO-1233zd. The experiments were carried out at saturation temperatures of 100°C, 115°C and 130°C and inlet and outlet qualities...... plate heat exchangers which allows for efficient heat transfer with a compact design. Accurate heat transfer correlations characterizing these devices are required from the design phase to the development of model-based control strategies. In this paper, the experimental heat transfer coefficient...

  7. Technology Development Program for an Advanced Potassium Rankine Power Conversion System Compatible with Several Space Reactor Designs

    Energy Technology Data Exchange (ETDEWEB)

    Yoder, G.L.

    2005-10-03

    This report documents the work performed during the first phase of the National Aeronautics and Space Administration (NASA), National Research Announcement (NRA) Technology Development Program for an Advanced Potassium Rankine Power Conversion System Compatible with Several Space Reactor Designs. The document includes an optimization of both 100-kW{sub e} and 250-kW{sub e} (at the propulsion unit) Rankine cycle power conversion systems. In order to perform the mass optimization of these systems, several parametric evaluations of different design options were investigated. These options included feed and reheat, vapor superheat levels entering the turbine, three different material types, and multiple heat rejection system designs. The overall masses of these Nb-1%Zr systems are approximately 3100 kg and 6300 kg for the 100- kW{sub e} and 250-kW{sub e} systems, respectively, each with two totally redundant power conversion units, including the mass of the single reactor and shield. Initial conceptual designs for each of the components were developed in order to estimate component masses. In addition, an overall system concept was presented that was designed to fit within the launch envelope of a heavy lift vehicle. A technology development plan is presented in the report that describes the major efforts that are required to reach a technology readiness level of 6. A 10-year development plan was proposed.

  8. RADIOACTIVE DEMONSTRATION OF FINAL MINERALIZED WASTE FORMS FOR HANFORD WASTE TREATMENT PLANT SECONDARY WASTE BY FLUIDIZED BED STEAM REFORMING USING THE BENCH SCALE REFORMER PLATFORM

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, C.; Burket, P.; Cozzi, A.; Daniel, W.; Jantzen, C.; Missimer, D.

    2012-02-02

    ceramic (mineral) waste form. The mineral waste form that is produced by co-processing waste with kaolin clay in an FBSR process has been shown to be as durable as LAW glass. Monolithing of the granular FBSR product is being investigated to prevent dispersion during transport or burial/storage, but is not necessary for performance. A Benchscale Steam Reformer (BSR) was designed and constructed at the SRNL to treat actual radioactive wastes to confirm the findings of the non-radioactive FBSR pilot scale tests and to qualify the waste form for applications at Hanford. BSR testing with WTP SW waste surrogates and associated analytical analyses and tests of granular products (GP) and monoliths began in the Fall of 2009, and then was continued from the Fall of 2010 through the Spring of 2011. Radioactive testing commenced in 2010 with a demonstration of Hanford's WTP-SW where Savannah River Site (SRS) High Level Waste (HLW) secondary waste from the Defense Waste Processing Facility (DWPF) was shimmed with a mixture of {sup 125/129}I and {sup 99}Tc to chemically resemble WTP-SW. Prior to these radioactive feed tests, non-radioactive simulants were also processed. Ninety six grams of radioactive granular product were made for testing and comparison to the non-radioactive pilot scale tests. The same mineral phases were found in the radioactive and non-radioactive testing.

  9. Weathering of almandine garnet: influence of secondary minerals on the rate-determining step, and implications for regolith-scale Al mobilization

    Science.gov (United States)

    Jason R. Price; Debra S. Bryan-Ricketts; Diane Anderson; Michael A. Velbel

    2013-01-01

    Secondary surface layers form by replacement of almandine garnet during chemical weathering. This study tested the hypothesis that the kinetic role of almandine's weathering products, and the consequent relationships of primary-mineral surface texture and specific assemblages of secondary minerals, both vary with the solid-solution-controlled variations in Fe and...

  10. Secondary parkinsonism

    Science.gov (United States)

    Parkinsonism - secondary; Atypical Parkinson disease ... to be less responsive to medical therapy than Parkinson disease. ... Unlike Parkinson disease, some types of secondary parkinsonism may stabilize or even improve if the underlying cause is treated. ...

  11. Determining a Cut-Off Point for Scores of the Breastfeeding Self-Efficacy Scale-Short Form: Secondary Data Analysis of an Intervention Study in Japan.

    Directory of Open Access Journals (Sweden)

    Keiko Nanishi

    Full Text Available Breastfeeding self-efficacy can be measured with the Breastfeeding Self-Efficacy Scale-Short Form (BSES-SF. Mothers with low BSES-SF scores stop exclusive breastfeeding prematurely, but specific interventions can prevent that undesirable outcome. Because those interventions can be expensive, often one must decide which mothers will receive them. For that purpose, a cut-off BSES-SF score would be useful, but none is available. Therefore, we aimed to assess the overall accuracy of BSES-SF scores as predictors of not practicing post-discharge exclusive breastfeeding, and to choose an appropriate cut-off score for making that prediction.This is a secondary data analysis of an intervention study. Data from 378 women in two non-Baby-Friendly Hospitals were analyzed. Participants were women in their third trimester who were 16 years of age or older, were able to read and write Japanese, were expected to have a singleton birth, and had completed the BSES-SF before discharge. BSES-SF scores were measured before discharge. Breastfeeding status was assessed 4 weeks and 12 weeks postpartum. Receiver Operating Characteristic (ROC curves were used to assess the predictive ability of the BSES-SF and to inform the choice of a cut-off point.For both of the ROC curves (4 and 12 weeks postpartum the area under the curve was 0.74. To obtain a high sensitivity, a cut-off score of 50 was chosen. With that cut-off score the sensitivity was 79% and the specificity was 52% 4 weeks postpartum, and they were 77% and 52%, respectively, 12 weeks postpartum.In conclusion, the BSES-SF has moderate overall accuracy to distinguish women who will not practice exclusive breastfeeding after discharge from those who will. At non-Baby-Friendly hospitals in Japan, interventions to support exclusive breastfeeding might be considered for new mothers who have BSES-SF scores that are less than or equal to 50.

  12. Determining a Cut-Off Point for Scores of the Breastfeeding Self-Efficacy Scale-Short Form: Secondary Data Analysis of an Intervention Study in Japan.

    Science.gov (United States)

    Nanishi, Keiko; Green, Joseph; Taguri, Masataka; Jimba, Masamine

    2015-01-01

    Breastfeeding self-efficacy can be measured with the Breastfeeding Self-Efficacy Scale-Short Form (BSES-SF). Mothers with low BSES-SF scores stop exclusive breastfeeding prematurely, but specific interventions can prevent that undesirable outcome. Because those interventions can be expensive, often one must decide which mothers will receive them. For that purpose, a cut-off BSES-SF score would be useful, but none is available. Therefore, we aimed to assess the overall accuracy of BSES-SF scores as predictors of not practicing post-discharge exclusive breastfeeding, and to choose an appropriate cut-off score for making that prediction. This is a secondary data analysis of an intervention study. Data from 378 women in two non-Baby-Friendly Hospitals were analyzed. Participants were women in their third trimester who were 16 years of age or older, were able to read and write Japanese, were expected to have a singleton birth, and had completed the BSES-SF before discharge. BSES-SF scores were measured before discharge. Breastfeeding status was assessed 4 weeks and 12 weeks postpartum. Receiver Operating Characteristic (ROC) curves were used to assess the predictive ability of the BSES-SF and to inform the choice of a cut-off point. For both of the ROC curves (4 and 12 weeks postpartum) the area under the curve was 0.74. To obtain a high sensitivity, a cut-off score of 50 was chosen. With that cut-off score the sensitivity was 79% and the specificity was 52% 4 weeks postpartum, and they were 77% and 52%, respectively, 12 weeks postpartum. In conclusion, the BSES-SF has moderate overall accuracy to distinguish women who will not practice exclusive breastfeeding after discharge from those who will. At non-Baby-Friendly hospitals in Japan, interventions to support exclusive breastfeeding might be considered for new mothers who have BSES-SF scores that are less than or equal to 50.

  13. Selection of cooling fluid for an organic Rankine cycle unit recovering heat on a container ship sailing in the Arctic region

    DEFF Research Database (Denmark)

    Suárez de la Fuente, Santiago; Larsen, Ulrik; Pierobon, Leonardo

    2017-01-01

    air as coolant. This paper explores the use of two different coolants, air and seawater, for an organic Rankine cycle (ORC) unit using the available waste heat in the scavenge air system of a container ship navigating in Arctic Circle. Using a two-step single objective optimisation process, detailed...

  14. Performance Evaluation of a HP/ORC (Heat Pump/Organic Rankine Cycle) System with Optimal Control of Sensible Thermal Storage

    DEFF Research Database (Denmark)

    Carmo, Carolina; Nielsen, Mads P.; Elmegaard, Brian

    2016-01-01

    come to contribute to the integration of intermittent renewables.This paper describes an innovative concept that consists of the addition of an Organic Rankine Cycle (ORC) toa combined solar system coupled to a ground-source heat pump (HP) in a single-family building. The ORC enables the use of solar...

  15. Design and optimisation of organic Rankine cycles for waste heat recovery in marine applications using the principles of natural selection

    DEFF Research Database (Denmark)

    Larsen, Ulrik; Pierobon, Leonardo; Haglind, Fredrik

    2013-01-01

    , boundary conditions, hazard levels and environmental concerns. A generally applicable methodology, based on the principles of natural selection, is presented and used to determine the optimum working fluid, boiler pressure and Rankine cycle process layout for scenarios related to marine engine heat......Power cycles using alternative working fluids are currently receiving significant attention. Selection of working fluid among many candidates is a key topic and guidelines have been presented. A general problem is that the selection is based on numerous criteria, such as thermodynamic performance...... recovery. Included in the solution domain are 109 fluids in sub and supercritical processes, and the process is adapted to the properties of the individual fluid. The efficiency losses caused by imposing process constraints are investigated to help propose a suitable process layout. Hydrocarbon dry type...

  16. Thermal-Economic Modularization of Small, Organic Rankine Cycle Power Plants for Mid-Enthalpy Geothermal Fields

    Directory of Open Access Journals (Sweden)

    Yodha Y. Nusiaputra

    2014-07-01

    Full Text Available The costs of the surface infrastructure in mid-enthalpy geothermal power systems, especially in remote areas, could be reduced by using small, modular Organic Rankine Cycle (ORC power plants. Thermal-economic criteria have been devised to standardize ORC plant dimensions for such applications. We designed a modular ORC to utilize various wellhead temperatures (120–170 °C, mass flow rates and ambient temperatures (−10–40 °C. A control strategy was developed using steady-state optimization, in order to maximize net power production at off-design conditions. Optimum component sizes were determined using specific investment cost (SIC minimization and mean cashflow (MCF maximization for three different climate scenarios. Minimizing SIC did not yield significant benefits, but MCF proved to be a much better optimization function.

  17. Experimental study on Rankine cycle evaporator efficiency intended for exhaust waste heat recovery of a diesel engine

    Directory of Open Access Journals (Sweden)

    Milkov Nikolay

    2017-01-01

    Full Text Available The paper pressents an experimental study of Rankine cycle evaporator efficiency. Water was chosen as the working fluid in the system. The experimental test was conducted on a test bench equipped with a burner charged by compressed fresh air. Generated exhaust gases parameters were previously determined over the diesel engine operating range (28 engine operating points were studied. For each test point the working fluid parameters (flow rate and evaporating pressure were varied. Thus, the enthalpy flow through the heat exchanger was determined. Heat exchanger was designed as 23 helical tubes are inserted. On the basis of the results, it was found out that efficiency varies from 25 % to 51,9 %. The optimal working fluid pressure is 20 bar at most of the operating points while the optimum fluid mass flow rate varies from 2 g/s to 10 g/s.

  18. Energy performance and economic evaluation of heat pump/organic rankine cycle system with sensible thermal storage

    DEFF Research Database (Denmark)

    Carmo, Carolina; Dumont, Olivier; Nielsen, Mads Pagh

    2016-01-01

    that consists of a ground-source heat pump with possibility of reversing operation as an ORC power cycle combined with solar heating in a single-family building is introduced. The ORC mode enables the use of solar energy in periods of no heat energy demand and reverses the heat pump cycle to supply electrical......-life conditions knowledge, the paper considers two different sensible energy storage (TES) configurations for the reversible heat pump/organic Rankine cycle (HP/ORC) system: a buffer tank for both space heating and domestic hot water and a hot water storage tank used exclusively for domestic hot water......The interaction between electrical and thermal energy demands represent a potential area for balancing supply and demand that could contribute to the integration of intermittent renewables in energy systems. To enable the interaction between thermal and electric energy, an innovative concept...

  19. Energy Performance and Economic Evaluation of Heat Pump/Organic Rankine Cycle System with Sensible Thermal Storage

    DEFF Research Database (Denmark)

    Carmo, C.; Dumont, O.; Nielsen, M. P.

    2016-01-01

    that consists of a ground-source heat pump with possibility of reversing operation as an ORC power cycle combined with solar heating in a single-family building is introduced. The ORC mode enables the use of solar energy in periods of no heat energy demand and reverses the heat pump cycle to supply electrical......-life conditions knowledge, the paper considers two different sensible energy storage (TES) configurations for the reversible heat pump/organic Rankine cycle (HP/ORC) system: a buffer tank for both space heating and domestic hot water and a hot water storage tank used exclusively for domestic hot water......The interaction between electrical and thermal energy demands represent a potential area for balancing supply and demand that could contribute to the integration of intermittent renewables in energy systems. To enable the interaction between thermal and electric energy, an innovative concept...

  20. Cogenerative Performance of a Wind − Gas Turbine − Organic Rankine Cycle Integrated System for Offshore Applications

    DEFF Research Database (Denmark)

    Bianchi, Michele; Branchini, Lisa; De Pascale, Andrea

    2016-01-01

    Gas Turbines (GT) are widely used for power generationin offshore oil and gas facilities, due to their high reliability,compactness and dynamic response capabilities. Small heavyduty and aeroderivative units in multiple arrangements aretypically used to offer larger load flexibility......, but limitedefficiency of such machines is the main drawback. A solutionto enhance the system performance, also in Combined Heat andPower (CHP) arrangement, is the implementation of OrganicRankine Cycle (ORC) systems at the bottom of the gas turbines.Moreover, the resulting GT-ORC combined cycle could befurther...... a 10MW offshorewind farm and three gas turbines rated for 16:5MW, eachone coupled with an 4:5MW ORC module. The ORC mainparameters are observed under different wind power fluctuations.Due to the non-programmable availability of wind and powerdemand, the part-load and dynamic characteristics...

  1. Study on the Characteristics of Expander Power Output Used for Offsetting Pumping Work Consumption in Organic Rankine Cycles

    Directory of Open Access Journals (Sweden)

    Yu-Ting Wu

    2014-07-01

    Full Text Available The circulation pump in an organic Rankine cycle (ORC increases the pressure of the liquid working fluid from low condensing pressure to high evaporating pressure, and the expander utilizes the pressure difference to generate work. A portion of the expander output power is used to offset the consumed pumping work, and the rest of the expander power is exactly the net work produced by the ORC system. Because of the relatively great theoretical pumping work and very low efficiency of the circulation pump reported in previous papers, the characteristics of the expander power used for offsetting the pumping work need serious consideration. In particular, the present work examines those characteristics. It is found that the characteristics of the expander power used for offsetting the pumping work are satisfactory only under the condition that the working fluid absorbs sufficient heat in the evaporator and its specific volume at the evaporator outlet is larger than or equal to a threshold value.

  2. 10-75-kWe-reactor-powered organic Rankine-cycle electric power systems (ORCEPS) study. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    1977-03-30

    This 10-75 kW(e) Reactor-ORCEPS study was concerned with the evaluation of several organic Rankine cycle energy conversion systems which utilized a /sup 235/U-ZrH reactor as a heat source. A liquid metal (NaK) loop employing a thermoelectric converter-powered EM pump was used to transfer the reactor energy to the organic working fluid. At moderate peak cycle temperatures (750/sup 0/F), power conversion unit cycle efficiencies of up to 25% and overall efficiencies of 20% can be obtained. The required operating life of seven years should be readily achievable. The CP-25 (toluene) working fluid cycle was found to provide the highest performance levels at the lowest system weights. Specific weights varies from 100 to 50 lb/kW(e) over the power level range 10 to 75 kW(e). (DLC)

  3. Structural optimisation of a high speed Organic Rankine Cycle generator using a genetic algorithm and a finite element method

    Energy Technology Data Exchange (ETDEWEB)

    Palko, S. [Machines Division, ABB industry Oy, Helsinki (Finland)

    1997-12-31

    The aim in this work is to design a 250 kW high speed asynchronous generator using a genetic algorithm and a finite element method for Organic Rankine Cycle. The characteristics of the induction motors are evaluated using two-dimensional finite element method (FEM) The movement of the rotor and the non-linearity of the iron is included. In numerical field problems it is possible to find several local extreme for an optimisation problem, and therefore the algorithm has to be capable of determining relevant changes, and to avoid trapping to a local minimum. In this work the electromagnetic (EM) losses at the rated point are minimised. The optimisation includes the air gap region. Parallel computing is applied to speed up optimisation. (orig.) 2 refs.

  4. Optimization of Cycle and Expander Design of an Organic Rankine Cycle Unit using Multi-Component Working Fluids

    DEFF Research Database (Denmark)

    Meroni, Andrea; Andreasen, Jesper Graa; Pierobon, Leonardo

    2016-01-01

    for an organic Rankine cycle unit utilizing waste heat from low temperature heat sources. The study addresses a case where the minimum temperature of the heat source is constrained and a case where no constraint is imposed. The former case is the wasteheat recovery from jacket cooling water of a marine diesel...... engine onboard a large ship, and the latter is representative of a low-temperature geothermal, solar or waste heat recovery application. Multi-component working fluids are investigated, as they allow improving the match between the temperature pro-files in the heat exchangers and, consequently, reducing...... the irreversibility in the ORC system. This work considers mixtures of R245fa/pentane and propane/isobutane. The use of multi-component working fluids typically results in increased heat transfer areas and different expander designs compared to purefluids. In order to properly account for turbine performance...

  5. Systematic Methods for Working Fluid Selection and the Design, Integration and Control of Organic Rankine Cycles—A Review

    Directory of Open Access Journals (Sweden)

    Patrick Linke

    2015-05-01

    Full Text Available Efficient power generation from low to medium grade heat is an important challenge to be addressed to ensure a sustainable energy future. Organic Rankine Cycles (ORCs constitute an important enabling technology and their research and development has emerged as a very active research field over the past decade. Particular focus areas include working fluid selection and cycle design to achieve efficient heat to power conversions for diverse hot fluid streams associated with geothermal, solar or waste heat sources. Recently, a number of approaches have been developed that address the systematic selection of efficient working fluids as well as the design, integration and control of ORCs. This paper presents a review of emerging approaches with a particular emphasis on computer-aided design methods.

  6. Megawatt-Scale Application of Thermoelectric Devices in Thermal Power Plants

    Science.gov (United States)

    Knox, A. R.; Buckle, J.; Siviter, J.; Montecucco, A.; McCulloch, E.

    2013-07-01

    Despite the recent investment in renewable and sustainable energy sources, over 95% of the UK's electrical energy generation relies on the use of thermal power plants utilizing the Rankine cycle. Advanced supercritical Rankine cycle power plants typically have a steam temperature in excess of 600°C at a pressure of 290 bar and yet still have an overall efficiency below 50%, with much of this wasted energy being rejected to the environment through the condenser/cooling tower. This paper examines the opportunity for large-scale application of thermoelectric heat pumps to modify the Rankine cycle in such plants by preheating the boiler feedwater using energy recovered from the condenser system at a rate of approximately 1 MWth per °C temperature rise. A derivation of the improved process cycle efficiency and breakeven coefficient of performance required for economic operation is presented for a typical supercritical 600-MWe installation.

  7. Large-scale analysis of secondary structure changes in proteins suggests a role for disorder-to-order transitions in nucleotide binding proteins.

    Science.gov (United States)

    Dan, Adi; Ofran, Yanay; Kliger, Yossef

    2010-02-01

    Conformational changes in proteins often involve secondary structure transitions. Such transitions can be divided into two types: disorder-to-order changes, in which a disordered segment acquires an ordered secondary structure (e.g., disorder to alpha-helix, disorder to beta-strand), and order-to-order changes, where a segment switches from one ordered secondary structure to another (e.g., alpha-helix to beta-strand, alpha-helix to turn). In this study, we explore the distribution of these transitions in the proteome. Using a comprehensive, yet highly conservative method, we compared solved three-dimensional structures of identical protein sequences, looking for differences in the secondary structures with which they were assigned. Protein chains in which such secondary structure transitions were detected, were classified into two sets according to the type of transition that is involved (disorder-to-order or order-to-order), allowing us to characterize each set by examining enrichment of gene ontology terms. The results reveal that the disorder-to-order set is significantly enriched with nucleotide binding proteins, whereas the order-to-order set is more diverse. Remarkably, further examination reveals that >22% of the purine nucleotide binding proteins include segments which undergo disorder-to-order transitions, suggesting that such transitions play an important role in this process. (c) 2009 Wiley-Liss, Inc.

  8. Challenging comparison of stroke scales

    Directory of Open Access Journals (Sweden)

    Kavian Ghandehari

    2013-01-01

    Full Text Available Stroke scales can be classified as clinicometric scales and functional impairment, handicap scales. All studies describing stroke scales were reviewed by internet searching engines with the final search performed on January 1, 2013. The following string of keywords was entered into search engines; stroke, scale, score and disability. Despite advantages of modified National Institute of Health Stroke Scale and Scandinavian stroke scale comparing to the NIHSS, including their simplification and less inter-rater variability; most of the stroke neurologists around the world continue using the NIHSS. The modified Rankin scale (mRS and Barthel index (BI are widely used functional impairment and disability scales. Distinction between grades of mRS is poorly defined. The Asian stroke disability scale is a simplified functional impairment, handicap scale which is as valid as mRS and BI. At the present time, the NIHSS, mRS and BI are routine stroke scales because physicians have used to work with these scales for more than two decades, although it could not be an acceptable reason. On the other side, results of previous stroke trials, which are the basis of stroke management guidelines are driven using these scales.

  9. Comparative Evaluation of Integrated Waste Heat Utilization Systems for Coal-Fired Power Plants Based on In-Depth Boiler-Turbine Integration and Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Shengwei Huang

    2018-01-01

    Full Text Available To maximize the system-level heat integration, three retrofit concepts of waste heat recovery via organic Rankine cycle (ORC, in-depth boiler-turbine integration, and coupling of both are proposed, analyzed and comprehensively compared in terms of thermodynamic and economic performances. For thermodynamic analysis, exergy analysis is employed with grand composite curves illustrated to identify how the systems are fundamentally and quantitatively improved, and to highlight key processes for system improvement. For economic analysis, annual revenue and investment payback period are calculated based on the estimation of capital investment of each component to identify the economic feasibility and competitiveness of each retrofit concept proposed. The results show that the in-depth boiler-turbine integration achieves a better temperature match of heat flows involved for different fluids and multi-stage air preheating, thus a significant improvement of power output (23.99 MW, which is much larger than that of the system with only ORC (6.49 MW. This is mainly due to the limitation of the ultra-low temperature (from 135 to 75 °C heat available from the flue gas for ORC. The thermodynamic improvement is mostly contributed by the reduction of exergy destruction within the boiler subsystem, which is eventually converted to mechanical power; while the exergy destruction within the turbine system is almost not changed for the three concepts. The selection of ORC working fluids is performed to maximize the power output. Due to the low-grade heat source, the cycle with R11 offers the largest additional net power generation but is not significantly better than the other preselected working fluids. Economically, the in-depth boiler-turbine integration is the most economic completive solution with a payback period of only 0.78 year. The ORC concept is less attractive for a sole application due to a long payback time (2.26 years. However, by coupling both

  10. Dataset of working conditions and thermo-economic performances for hybrid organic Rankine plants fed by solar and low-grade energy sources.

    Science.gov (United States)

    Scardigno, Domenico; Fanelli, Emanuele; Viggiano, Annarita; Braccio, Giacobbe; Magi, Vinicio

    2016-06-01

    This article provides the dataset of operating conditions of a hybrid organic Rankine plant generated by the optimization procedure employed in the research article "A genetic optimization of a hybrid organic Rankine plant for solar and low-grade energy sources" (Scardigno et al., 2015) [1]. The methodology used to obtain the data is described. The operating conditions are subdivided into two separate groups: feasible and unfeasible solutions. In both groups, the values of the design variables are given. Besides, the subset of feasible solutions is described in details, by providing the thermodynamic and economic performances, the temperatures at some characteristic sections of the thermodynamic cycle, the net power, the absorbed powers and the area of the heat exchange surfaces.

  11. Flow boiling heat transfer and pressure drop characteristics of R134a, R1234yf and R1234ze in a plate heat exchanger for organic Rankine cycle units

    DEFF Research Database (Denmark)

    Zhang, Ji; Desideri, Adriano; Kærn, Martin Ryhl

    2017-01-01

    . This paper is aimed at obtaining flow boiling heat transfer and pressure drop characteristics in a plate heat exchanger under the working conditions prevailing in the evaporator of organic Rankine cycle units. Two hydrofluoroolefins R1234yf and R1234ze, and one hydrofluorocarbon R134a, were selected......The optimal design of the evaporator is one of the key issues to improve the efficiency and economics of organic Rankine cycle units. The first step in studying the evaporator design is to understand the thermal-hydraulic performance of the working fluid in the evaporator of organic Rankine cycles......, respectively. The working conditions covered relatively high saturation temperatures (corresponding reduced pressures of 0.35-0.74), which are prevailing in organic Rankine cycles yet absent in the open literature. The experimental data were compared with existing correlations, and new correlations were...

  12. Optimization of Biomass-Fuelled Combined Cooling, Heating and Power (CCHP) Systems Integrated with Subcritical or Transcritical Organic Rankine Cycles (ORCs)

    OpenAIRE

    Daniel Maraver; Sylvain Quoilin; Javier Royo

    2014-01-01

    This work is focused on the thermodynamic optimization of Organic Rankine Cycles (ORCs), coupled with absorption or adsorption cooling units, for combined cooling heating and power (CCHP) generation from biomass combustion. Results were obtained by modelling with the main aim of providing optimization guidelines for the operating conditions of these types of systems, specifically the subcritical or transcritical ORC, when integrated in a CCHP system to supply typical heating and cooling deman...

  13. Performance Analysis and Working Fluid Selection of a Supercritical Organic Rankine Cycle for Low Grade Waste Heat Recovery

    Directory of Open Access Journals (Sweden)

    Yourong Li

    2012-08-01

    Full Text Available The performance analysis of a supercritical organic Rankine cycle system driven by exhaust heat using 18 organic working fluids is presented. Several parameters, such as the net power output, exergy efficiency, expander size parameter (SP, and heat exchanger requirement of evaporator and the condenser, were used to evaluate the performance of this recovery cycle and screen the working fluids. The results reveal that in most cases, raising the expander inlet temperature is helpful to improve the net power output and the exergy efficiency. However, the effect of the expander inlet pressure on those parameters is related to the expander inlet temperature and working fluid used. Either lower expander inlet temperature and pressure, or higher expander inlet temperature and pressure, generally makes the net power output more. Lower expander inlet temperature results in larger total heat transfer requirement and expander size. According to the screening criteria of both the higher output and the lower investment, the following working fluids for the supercritical ORC system are recommended: R152a and R143a.

  14. Organic Rankine-cycle power systems working fluids study: Topical report No. 1: Fluorinol 85. [85 mole % trofluoroethanol in water

    Energy Technology Data Exchange (ETDEWEB)

    Jain, M.L.; Demirgian, J.C.; Cole, R.L.

    1986-09-01

    An investigation to experimentally determine the thermal stability limits and degradation rates of Fluorinol 85 as a function of maximum cycle temperatures was initiated in 1982. Following the design and construction of a dynamic test loop capable of simulating the thermodynamic conditions of possible prototypical organic Rankine-cycle (ORC) power systems, several test runs were completed. The Fluorinol 85 test loop was operated for about 3800 h, covering a temperature range of 525-600/sup 0/F. Both liquid and noncondensable vapor (gas) samples were drawn periodically and analyzed using capillary column gas chromatography, gas chromatography/mass spectrometry and mass spectrometry. Results indicate that Fluorinol 85 would not decompose significantly over an extended period of time, up to a maximum cycle temperature of 550/sup 0/F. However, 506-h data at 575/sup 0/F show initiation of significant degradation. The 770-h data at 600/sup 0/F, using a fresh charge of Fluorinol 85, indicate an annual degradation rate of more than 17.2%. The most significant degradation product observed is hydrofluoric acid, which could cause severe corrosion in an ORC system. Devices to remove the hydrofluoric acid and prevent extreme temperature excursions are necessary for any ORC system using Fluorinol 85 as a working fluid.

  15. Exergy analysis of an integrated solid oxide fuel cell and organic Rankine cycle for cooling, heating and power production

    Energy Technology Data Exchange (ETDEWEB)

    Al-Sulaiman, Fahad A. [Mechanical and Aerospace Engineering Department, Carleton University 1125 Colonel By Drive, Ottawa, Ontario (Canada); Dincer, Ibrahim [Faculty of Engineering and Applied Science, University of Ontario Institute of Technology 2000 Simcoe Street North, Oshawa, Ontario (Canada); Hamdullahpur, Feridun [Mechanical and Mechatronics Engineering Department, University of Waterloo, 200 University Avenue West, Waterloo, Ontario (Canada)

    2010-04-15

    The study examines a novel system that combined a solid oxide fuel cell (SOFC) and an organic Rankine cycle (ORC) for cooling, heating and power production (trigeneration) through exergy analysis. The system consists of an SOFC, an ORC, a heat exchanger and a single-effect absorption chiller. The system is modeled to produce a net electricity of around 500 kW. The study reveals that there is 3-25% gain on exergy efficiency when trigeneration is used compared with the power cycle only. Also, the study shows that as the current density of the SOFC increases, the exergy efficiencies of power cycle, cooling cogeneration, heating cogeneration and trigeneration decreases. In addition, it was shown that the effect of changing the turbine inlet pressure and ORC pump inlet temperature are insignificant on the exergy efficiencies of the power cycle, cooling cogeneration, heating cogeneration and trigeneration. Also, the study reveals that the significant sources of exergy destruction are the ORC evaporator, air heat exchanger at the SOFC inlet and heating process heat exchanger. (author)

  16. An Innovative Application of a Solar Storage Wall Combined with the Low-Temperature Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Tzu-Chen Hung

    2014-01-01

    Full Text Available The objective of this study is to collect energy on the waste heat from air produced by solar ventilation systems. This heat used for electricity generation by an organic Rankine cycle (ORC system was implemented. The advantages of this method include the use of existing building’s wall, and it also provides the region of energy scarcity for reference. This is also an innovative method, and the results will contribute to the efforts made toward improving the design of solar ventilation in the field of solar thermal engineering. In addition, ORC system would help generate electricity and build a low-carbon building. This study considered several critical parameters such as length of the airflow channel, intensity of solar radiation, pattern of the absorber plate, stagnant air layer, and operating conditions. The simulation results show that the highest outlet temperature and heat collecting efficiency of solar ventilation system are about 120°C and 60%, respectively. The measured ORC efficiency of the system was 6.2%. The proposed method is feasible for the waste heat from air produced by ventilation systems.

  17. Analysis and optimization of three main organic Rankine cycle configurations using a set of working fluids with different thermodynamic behaviors

    Science.gov (United States)

    Hamdi, Basma; Mabrouk, Mohamed Tahar; Kairouani, Lakdar; Kheiri, Abdelhamid

    2017-06-01

    Different configurations of organic Rankine cycle (ORC) systems are potential thermodynamic concepts for power generation from low grade heat. The aim of this work is to investigate and optimize the performances of the three main ORC systems configurations: basic ORC, ORC with internal heat exchange (IHE) and regenerative ORC. The evaluation for those configurations was performed using seven working fluids with typical different thermodynamic behaviours (R245fa, R601a, R600a, R227ea, R134a, R1234ze and R1234yf). The optimization has been performed using a genetic algorithm under a comprehensive set of operative parameters such as the fluid evaporating temperature, the fraction of flow rate or the pressure at the steam extracting point in the turbine. Results show that there is no general best ORC configuration for all those fluids. However, there is a suitable configuration for each fluid. Contribution to the topical issue "Materials for Energy harvesting, conversion and storage II (ICOME 2016)", edited by Jean-Michel Nunzi, Rachid Bennacer and Mohammed El Ganaoui

  18. Technical Analysis of Organic Rankine Cycle System Using Low-Temperature Source to Generate Electricity in Ship

    Directory of Open Access Journals (Sweden)

    Akram Faisal

    2017-01-01

    Full Text Available Nowadays, the shipping sector has growth rapidly as followed by the increasing of world population and the demands for public transportation via sea. This issue entails the large attention on emission, energy efficiency and fuel consumption on the ship. Waste Heat Recovery (WHR is one of the solution to overcome the mentioned issue and one of the WHR method is by installing Organic Rankine Cycle (ORC system in ship. ORC demonstrate to recover and exploit the low temperature waste heat rejected by the ship power generation plant. The main source of heat to be utilized is obtained from container ship (7900 kW BHP, DWT 10969 mt ship jacket water cooling system and use R-134a as a refrigerant. The main equipment consists of evaporator, condenser, pump and steam turbine to generate the electricity. The main objective is to quantifying the estimation of electrical power which can be generated at typical loads of the main engine. As the final result of analysis, the ORC system is able to generate the electricity power ranged from 77,5% - 100% of main engine load producing power averagely 57,69 kW.

  19. Study on Mixed Working Fluids with Different Compositions in Organic Rankine Cycle (ORC Systems for Vehicle Diesel Engines

    Directory of Open Access Journals (Sweden)

    Kai Yang

    2014-08-01

    Full Text Available One way to increase the thermal efficiency of vehicle diesel engines is to recover waste heat by using an organic Rankine cycle (ORC system. Tests were conducted to study the running performances of diesel engines in the whole operating range. The law of variation of the exhaust energy rate under various engine operating conditions was also analyzed. A diesel engine-ORC combined system was designed, and relevant evaluation indexes proposed. The variation of the running performances of the combined system under various engine operating conditions was investigated. R245fa and R152a were selected as the components of the mixed working fluid. Thereafter, six kinds of mixed working fluids with different compositions were presented. The effects of mixed working fluids with different compositions on the running performances of the combined system were revealed. Results show that the running performances of the combined system can be improved effectively when mass fraction R152a in the mixed working fluid is high and the engine operates with high power. For the mixed working fluid M1 (R245fa/R152a, 0.1/0.9, by mass fraction, the net power output of the combined system reaches the maximum of 34.61 kW. Output energy density of working fluid (OEDWF, waste heat recovery efficiency (WHRE, and engine thermal efficiency increasing ratio (ETEIR all reach their maximum values at 42.7 kJ/kg, 10.90%, and 11.29%, respectively.

  20. About the prediction of Organic Rankine Cycles performances integrating local high-fidelity turbines simulation and uncertainties

    Science.gov (United States)

    Congedo, Pietro; de Santis, Dante; Geraci, Gianluca

    2014-11-01

    Organic Rankine Cycles (ORCs) are of key-importance when exploiting energy systems with a high efficiency. The variability of renewable heat sources makes more complex the global performance prediction of a cycle. The thermodynamic properties of the complex fluids used in the process are another source of uncertainty. The need for a predictive and robust simulation tool of ORCs remains strong. A high-order accurate Residual Distribution scheme has been recently developed for efficiently computing a turbine stage on unstructured grids, including advanced equations of state in order to take into account the complex fluids used in ORCs. Advantages in using high-order methods have been highlighted, in terms of number of degrees of freedom and computational time used, for computing the numerical solution with a greater accuracy compared to lower-order methods, even for shocked flows. The objective of this work is to quantify the numerical error with respect to the various sources of uncertainty of the ORC turbine, thus providing a very high-fidelity prediction in the coupled physical/stochastic space.

  1. Modelling the Influence of Climate on the Performance of the Organic Rankine Cycle for Industrial Waste Heat Recovery

    Directory of Open Access Journals (Sweden)

    Ivan Korolija

    2016-05-01

    Full Text Available This paper describes a study of the relative influences of different system design decisions upon the performance of an organic Rankine cycle (ORC used to generate electricity from foundry waste heat. The design choices included concern the working fluid, whether to use a regenerator and the type of condenser. The novelty of the research lies in its inclusion of the influence of both the ORC location and the auxiliary electricity used by the pumps and fans in the ORC power system. Working fluids suitable for high temperature applications are compared, including three cyclic siloxanes, four linear siloxanes and three aromatic fluids. The ORC is modelled from first principles and simulation runs carried out using weather data for 106 European locations and a heat input profile that was derived from empirical data. The impact of design decisions upon ORC nominal efficiency is reported followed by the impact upon annual system efficiency in which variations in heat input and the condition of outdoor air over a year are considered. The main conclusion is that the location can have a significant impact upon the efficiency of ORC systems due to the influence of climate upon the condenser and auxiliary electricity requirements.

  2. Performance analysis of exhaust heat recovery using organic Rankine cycle in a passenger car with a compression ignition engine

    Science.gov (United States)

    Ghilvacs, M.; Prisecaru, T.; Pop, H.; Apostol, V.; Prisecaru, M.; Pop, E.; Popescu, Gh; Ciobanu, C.; Mohanad, A.; Alexandru, A.

    2016-08-01

    Compression ignition engines transform approximately 40% of the fuel energy into power available at the crankshaft, while the rest part of the fuel energy is lost as coolant, exhaust gases and other waste heat. An organic Rankine cycle (ORC) can be used to recover this waste heat. In this paper, the characteristics of a system combining a compression ignition engine with an ORC which recover the waste heat from the exhaust gases are analyzed. The performance map of the diesel engine is measured on an engine test bench and the heat quantities wasted by the exhaust gases are calculated over the engine's entire operating region. Based on this data, the working parameters of ORC are defined, and the performance of a combined engine-ORC system is evaluated across this entire region. The results show that the net power of ORC is 6.304kW at rated power point and a maximum of 10% reduction in brake specific fuel consumption can be achieved.

  3. Optimal design of solid oxide fuel cell, ammonia-water single effect absorption cycle and Rankine steam cycle hybrid system

    Science.gov (United States)

    Mehrpooya, Mehdi; Dehghani, Hossein; Ali Moosavian, S. M.

    2016-02-01

    A combined system containing solid oxide fuel cell-gas turbine power plant, Rankine steam cycle and ammonia-water absorption refrigeration system is introduced and analyzed. In this process, power, heat and cooling are produced. Energy and exergy analyses along with the economic factors are used to distinguish optimum operating point of the system. The developed electrochemical model of the fuel cell is validated with experimental results. Thermodynamic package and main parameters of the absorption refrigeration system are validated. The power output of the system is 500 kW. An optimization problem is defined in order to finding the optimal operating point. Decision variables are current density, temperature of the exhaust gases from the boiler, steam turbine pressure (high and medium), generator temperature and consumed cooling water. Results indicate that electrical efficiency of the combined system is 62.4% (LHV). Produced refrigeration (at -10 °C) and heat recovery are 101 kW and 22.1 kW respectively. Investment cost for the combined system (without absorption cycle) is about 2917 kW-1.

  4. Thermo-Economic Analysis of Zeotropic Mixtures and Pure Working Fluids in Organic Rankine Cycles for Waste Heat Recovery

    Directory of Open Access Journals (Sweden)

    Florian Heberle

    2016-03-01

    Full Text Available We present a thermo-economic analysis of an Organic Rankine Cycle (ORC for waste heat recovery. A case study for a heat source temperature of 150 °C and a subcritical, saturated cycle is performed. As working fluids R245fa, isobutane, isopentane, and the mixture of isobutane and isopentane are considered. The minimal temperature difference in the evaporator and the condenser, as well as the mixture composition are chosen as variables in order to identify the most suitable working fluid in combination with optimal process parameters under thermo-economic criteria. In general, the results show that cost-effective systems have a high minimal temperature difference ΔTPP,C at the pinch-point of the condenser and a low minimal temperature difference ΔTPP,E at the pinch-point of the evaporator. Choosing isobutane as the working fluid leads to the lowest costs per unit exergy with 52.0 €/GJ (ΔTPP,E = 1.2 K; ΔTPP,C = 14 K. Considering the major components of the ORC, specific costs range between 1150 €/kW and 2250 €/kW. For the zeotropic mixture, a mole fraction of 90% isobutane leads to the lowest specific costs per unit exergy. A further analysis of the ORC system using isobutane shows high sensitivity of the costs per unit exergy for the selected cost estimation methods and for the isentropic efficiency of the turbine.

  5. Performance of Siloxane Mixtures in a High-Temperature Organic Rankine Cycle Considering the Heat Transfer Characteristics during Evaporation

    Directory of Open Access Journals (Sweden)

    Theresa Weith

    2014-08-01

    Full Text Available The application of the Organic Rankine Cycle to high temperature heat sources is investigated on the case study of waste heat recovery from a selected biogas plant. Two different modes of operation are distinguished: pure electric power and combined heat and power generation. The siloxanes hexamethyldisiloxane (MM and octamethyltrisiloxane (MDM are chosen as working fluids. Moreover, the effect of using mixtures of these components is analysed. Regarding pure electricity generation, process simulations using the simulation tool Aspen Plus show an increase in second law efficiency of 1.3% in case of 97/03 wt % MM/MDM-mixture, whereas for the combined heat and power mode a 60/40 wt % MM/MDM-mixture yields the highest efficiency with an increase of nearly 3% compared to most efficient pure fluid. Next to thermodynamic analysis, measurements of heat transfer coefficients of these siloxanes as well as their mixtures are conducted and Kandlikar’s correlation is chosen to describe the results. Based on that, heat exchanger areas for preheater and evaporator are calculated in order to check whether the poorer heat transfer characteristics of mixtures devalue their efficiency benefit due to increased heat transfer areas. Results show higher heat transfer areas of 0.9% and 14%, respectively, compared to MM.

  6. Test Requirements and Conceptual Design for a Potassium Test Loop to Support an Advanced Potassium Rankine Cycle Power Conversion Systems

    Energy Technology Data Exchange (ETDEWEB)

    Yoder, JR.G.L.

    2006-03-08

    Parameters for continuing the design and specification of an experimental potassium test loop are identified in this report. Design and construction of a potassium test loop is part of the Phase II effort of the project ''Technology Development Program for an Advanced Potassium Rankine Power Conversion System''. This program is supported by the National Aeronautics and Space Administration. Design features for the potassium test loop and its instrumentation system, specific test articles, and engineered barriers for ensuring worker safety and protection of the environment are described along with safety and environmental protection requirements to be used during the design process. Information presented in the first portion of this report formed the basis to initiate the design phase of the program; however, the report is a living document that can be changed as necessary during the design process, reflecting modifications as additional design details are developed. Some portions of the report have parameters identified as ''to be determined'' (TBD), reflecting the early stage of the overall process. In cases where specific design values are presently unknown, the report attempts to document the quantities that remain to be defined in order to complete the design of the potassium test loop and supporting equipment.

  7. Economic assessment of greenhouse gas reduction through low-grade waste heat recovery using organic Rankine cycle (ORC)

    Energy Technology Data Exchange (ETDEWEB)

    Imran, Muhammad; Park, Byung Sik; Kim, Hyouck Ju; Usman, Muhammad [University of Science and Technology, Daejeon (Korea, Republic of); Lee, Dong Hyun [Korea Institute of Energy Research, Daejeon (Korea, Republic of)

    2015-02-15

    Low-grade waste heat recovery technologies reduce the environmental impact of fossil fuels and improve overall efficiency. This paper presents the economic assessment of greenhouse gas (GHG) reduction through waste heat recovery using organic Rankine cycle (ORC). The ORC engine is one of the mature low temperature heat engines. The low boiling temperature of organic working fluid enables ORC to recover low-temperature waste heat. The recovered waste heat is utilized to produce electricity and hot water. The GHG emissions for equivalent power and hot water from three fossil fuels-coal, natural gas, and diesel oil-are estimated using the fuel analysis approach and corresponding emission factors. The relative decrease in GHG emission is calculated using fossil fuels as the base case. The total cost of the ORC system is used to analyze the GHG reduction cost for each of the considered fossil fuels. A sensitivity analysis is also conducted to investigate the effect of the key parameter of the ORC system on the cost of GHG reduction. Throughout the 20-year life cycle of the ORC plant, the GHG reduction cost for R245fa is 0.02 $/kg to 0.04 $/kg and that for pentane is 0.04 $/kg to 0.05 $/kg. The working fluid, evaporation pressure, and pinch point temperature difference considerably affect the GHG emission.

  8. Economic, Energetic, and Environmental Performance of a Solar Powered Organic Rankine Cycle with Electric Energy Storage in Different Commercial Buildings

    Directory of Open Access Journals (Sweden)

    Emily Spayde

    2018-01-01

    Full Text Available This paper presents an analysis to determine the economic, energetic, and environmental benefits that could be obtained from the implementation of a combined solar-power organic Rankine cycle (ORC with electric energy storage (EES to supply electricity to several commercial buildings including a large office, a small office, and a full service restaurant. The operational strategy for the ORC-EES system consists in the ORC charging the EES when the irradiation level is sufficient to generate power, and the EES providing electricity to the building when there is not irradiation (i.e., during night time. Electricity is purchased from the utility grid unless it is provided by the EES. The potential of the proposed system to reduce primary energy consumption (PEC, carbon dioxide emission (CDE, and cost was evaluated. Furthermore, the available capital cost for a variable payback period for the ORC-EES system was determined for each of the evaluated buildings. The effect of the number of solar collectors on the performance of the ORC-EES is also studied. Results indicate that the proposed ORC-EES system is able to satisfy 11%, 13%, and 18% of the electrical demand for the large office, the small office and the restaurant, respectively.

  9. Secondary amenorrhea

    Science.gov (United States)

    ... a lot of weight suddenly (for example, from strict or extreme diets or after gastric bypass surgery ) ... secondary amenorrhea and precocious puberty: etiology, diagnostic evaluation, management. In: Lentz GM, Lobo RA, Gershenson DM, Katz ...

  10. Predictors of Information Technology Integration in Secondary Schools: Evidence from a Large Scale Study of More than 30,000 Students.

    Science.gov (United States)

    Hew, Khe Foon; Tan, Cheng Yong

    2016-01-01

    The present study examined the predictors of information technology (IT) integration in secondary school mathematics lessons. The predictors pertained to IT resource availability in schools, school contextual/institutional variables, accountability pressure faced by schools, subject culture in mathematics, and mathematics teachers' pedagogical beliefs and practices. Data from 32,256 secondary school students from 2,519 schools in 16 developed economies who participated in the Program for International Student Assessment (PISA) 2012 were analyzed using hierarchical linear modeling (HLM). Results showed that after controlling for student-level (gender, prior academic achievement and socioeconomic status) and school-level (class size, number of mathematics teachers) variables, students in schools with more computers per student, with more IT resources, with higher levels of IT curricular expectations, with an explicit policy on the use of IT in mathematics, whose teachers believed in student-centered teaching-learning, and whose teachers provided more problem-solving activities in class reported higher levels of IT integration. On the other hand, students who studied in schools with more positive teacher-related school learning climate, and with more academically demanding parents reported lower levels of IT integration. Student-related school learning climate, principal leadership behaviors, schools' public posting of achievement data, tracking of school's achievement data by administrative authorities, and pedagogical and curricular differentiation in mathematics lessons were not related to levels of IT integration. Put together, the predictors explained a total of 15.90% of the school-level variance in levels of IT integration. In particular, school IT resource availability, and mathematics teachers' pedagogical beliefs and practices stood out as the most important determinants of IT integration in mathematics lessons.

  11. Predictors of Information Technology Integration in Secondary Schools: Evidence from a Large Scale Study of More than 30,000 Students.

    Directory of Open Access Journals (Sweden)

    Khe Foon Hew

    Full Text Available The present study examined the predictors of information technology (IT integration in secondary school mathematics lessons. The predictors pertained to IT resource availability in schools, school contextual/institutional variables, accountability pressure faced by schools, subject culture in mathematics, and mathematics teachers' pedagogical beliefs and practices. Data from 32,256 secondary school students from 2,519 schools in 16 developed economies who participated in the Program for International Student Assessment (PISA 2012 were analyzed using hierarchical linear modeling (HLM. Results showed that after controlling for student-level (gender, prior academic achievement and socioeconomic status and school-level (class size, number of mathematics teachers variables, students in schools with more computers per student, with more IT resources, with higher levels of IT curricular expectations, with an explicit policy on the use of IT in mathematics, whose teachers believed in student-centered teaching-learning, and whose teachers provided more problem-solving activities in class reported higher levels of IT integration. On the other hand, students who studied in schools with more positive teacher-related school learning climate, and with more academically demanding parents reported lower levels of IT integration. Student-related school learning climate, principal leadership behaviors, schools' public posting of achievement data, tracking of school's achievement data by administrative authorities, and pedagogical and curricular differentiation in mathematics lessons were not related to levels of IT integration. Put together, the predictors explained a total of 15.90% of the school-level variance in levels of IT integration. In particular, school IT resource availability, and mathematics teachers' pedagogical beliefs and practices stood out as the most important determinants of IT integration in mathematics lessons.

  12. The psychometric properties of the Snijders-Oomen Individual Non-verbal Intelligence Scale Revised (SON-R) for secondary school learners from culturally diverse communities

    OpenAIRE

    2012-01-01

    M.A. Traditional measures often used in the assessment of cognitive functions of individuals, are regarded as unsuitable for two reasons. Firstly, since a particular language is utilized in the test items and instructions of most cognitive tests, the overall lower verbal test scores of culturally diverse individuals often is an indicator of poor verbal knowledge and language proficiency that in effect has a bearing on an invalid lower Full Scale IQ score. The verbal item content fail to pr...

  13. [Secondary dressings].

    Science.gov (United States)

    Philippe, Anne

    2016-01-01

    Wound management imposes a defined approach to each phase of healing and thereby the need for in-depth knowledge of the various medical devices available: primary and secondary dressings. Secondary dressings are essential as they have an impact on the efficacy of the primary dressing. Their role is to protect, reinforce and cover the primary dressing. In practice, it is usually nurses who have the responsibility of selecting and prescribing the most suitable dressing for the wound. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  14. Secondary dyslipidaemia

    African Journals Online (AJOL)

    Repro

    (e.g. metabolic syndrome, syndrome X), play a dominant role in causing dyslipi- daemia and in the genesis of coronary artery disease (CAD). Secondary causes of dyslipidaemia should always be consid- ered and may be important for several reasons: • they uncover other underlying diseases that require specific treatment.

  15. Design and development of an automotive organic Rankine-cycle powerplant with a reciprocating expander. Final report. Volume II. Detailed discussion

    Energy Technology Data Exchange (ETDEWEB)

    1977-09-01

    Work performed for the design and development of an organic Rankine-cycle engine for automobile propulsion is reported. An automotive power plant using an organic Rankine-cycle system with a reciprocating expander has been designed, built, and tested on an engine dynamometer in a preprototype configuration. The system is designed to provide performance approximately equivalent to that of a 351-CID internal combustion engine in the reference car, a 1972 Ford Galaxie 500. A description of the preprototype system, major components, and results from component and system testing are presented. The fuel economy based on steady-state measurements is estimated to be 10.2 mpg over the federal driving cycle with a maximum of 16 mpg at 30 mph. Projections of steady-state emission measurements show compliance with the 1970 Clean Air Act standards for 1978 vehicle emissions. The levels for unburned hydrocarbons, carbon monoxide, and oxides of nitrogen were 41 percent, 6 percent, and 69 percent of the standards, respectively. At the conclusion of the preprototype phase of the program, a prototype design effort was initiated to upgrade and improve the performance of the preprototype system. The reference vehicle for this prototype design is a compact car in the weight class of a 1974 Ford Pinto. The results of this design study, including performance projections, are also presented.

  16. Calculation of wave resistance by using Kochin function in the Rankine source method; Rankinsosuho ni okeru kochin kansu wo mochiita zoha teiko keisan

    Energy Technology Data Exchange (ETDEWEB)

    Yasukawa, H. [Mitsubishi Heavy Industries, Ltd., Tokyo (Japan)

    1997-10-01

    In order to avoid negative wave resistance (which is physically incomprehensible) generated in calculating wave resistance by using the Rankine source method, a proposal was made on a wave resistance calculation method using the Kochin function which describes behavior of speed potential in regions far apart from a hull. The Baba`s condition was used as a free surface condition for the speed potential which expresses wave motions around a hull. This has allowed a new Kochin function which uses as unknown the speed potential on the hull surface and the free surface near the hull to be defined and combined with the Rankine source method. A comparison was made between the calculated values for wave resistance, hull subsidence and trim change of an ore transporting vessel (SR107 type of ship) in a fully loaded condition and the result of water tank tests. The wave resistance values derived from pressure integration have all become negative when the Froude number is from 0.1 to 0.2, while no negative resistance has appeared in the calculations by using the Kochin function, but the result has agreed with that of the water tank tests. Accuracy of the calculations at low speeds was improved. The trim change in the calculations was slightly smaller than that in the water tank tests. The subsidence showed a good agreement. 7 refs., 1 fig.

  17. Propuesta de una escala para medir la calidad del servicio de los centros de atención secundaria de salud Proposal of a scale to measure the quality of service in secondary healthcare centers

    Directory of Open Access Journals (Sweden)

    Eduardo Torres Moraga

    2008-08-01

    Full Text Available El Ministerio de Salud en Chile se ha planteado como uno de sus principales objetivos, proveer servicios acorde a las expectativas de la población. Para lograrlo, se requiere necesariamente, conocer cuál es la calidad del servicio ofrecida por los centros de salud. En Chile, los centros de atención secundaria, no han desarrollado escalas de calidad del servicio que tengan un buen grado de validez, fiabilidad y dimensionalidad. Este artículo, propone una escala que cumpla estas condiciones, para medir de manera óptima la calidad del servicio que los Centros de Atención Secundaria ofrecen a sus pacientes. Para lograr este objetivo, se aplicó una encuesta estructurada y posteriormente se realizó un exhaustivo análisis psicométrico de los datos, a través de una serie de análisis exploratorios y confirmatorios que incluyó ecuaciones estructurales. Este estudio permitió construir y proponer una escala fiable, válida y con buen grado de dimensionalidad, compuesta por cinco subescalas claramente relacionadas e integradas en un único constructo. Estas son: confiabilidad, empatía, capacidad de respuesta, accesibilidad y tangibles.Chile's Ministry of Health has made it one of its main objectives to provide services that meet the expectations of the population. To achieve this, it is necessary to know what the quality of service offered by healthcare centers is like. In Chile, secondary healthcare centers have not developed quality of service scales that have a good level of validity, dependability, and dimensionality. This article proposes a scale that fulfills these conditions so as to measure in an optimal way the quality of service that secondary healthcare centers offer their patients. To achieve this objective, a structured survey was applied, followed by an exhaustive psychometric analysis of the facts through exploratory and confirmatory analysis that included structural equations. This study allowed for the construction and

  18. A full-scale study on thermal degradation of polychlorinated dibenzo- p-dioxins and dibenzofurans in municipal solid waste incinerator fly ash and its secondary air pollution control in China.

    Science.gov (United States)

    Gao, Xingbao; Ji, Bingjing; Yan, Dahai; Huang, Qifei; Zhu, Xuemei

    2017-04-01

    Degradation of polychlorinated dibenzo- p-dioxins and dibenzofurans in municipal solid waste incinerator fly ash is beneficial to its risk control. Fly ash was treated in a full-scale thermal degradation system (capacity 1 t d-1) to remove polychlorinated dibenzo- p-dioxins and dibenzofurans. Apart from the confirmation of the polychlorinated dibenzo- p-dioxin and dibenzofuran decomposition efficiency, we focused on two major issues that are the major obstacles for commercialising this decomposition technology in China, desorption and regeneration of dioxins and control of secondary air pollution. The toxic equivalent quantity values of polychlorinated dibenzo- p-dioxins and dibenzofurans decreased to solid waste incinerator economiser, and then co-processed in the air pollution control system. The degradation furnace released relatively large amounts of cadmium, lead and polychlorinated dibenzo- p-dioxins and dibenzofurans compared with the municipal solid waste incinerator, but the amounts emitted to the atmosphere did not exceed the Chinese national emission limits. Thermal degradation can therefore be used as a polychlorinated dibenzo- p-dioxin and dibenzofuran abatement method for municipal solid waste incinerator source in China.

  19. Energy Conversion Alternatives Study (ECAS), Westinghouse phase 1. Volume 7: Metal vapor Rankine topping-steam bottoming cycles. [energy conversion efficiency in electric power plants

    Science.gov (United States)

    Deegan, P. B.

    1976-01-01

    Adding a metal vapor Rankine topper to a steam cycle was studied as a way to increase the mean temperature at which heat is added to the cycle to raise the efficiency of an electric power plant. Potassium and cesium topping fluids were considered. Pressurized fluidized bed or pressurized (with an integrated low-Btu gasifier) boilers were assumed. Included in the cycles was a pressurizing gas turbine with its associated recuperator, and a gas economizer and feedwater heater. One of the ternary systems studied shows plant efficiency of 42.3% with a plant capitalization of $66.7/kW and a cost of electricity of 8.19 mills/MJ (29.5 mills/kWh).

  20. A Mathematical Model of Hourly Solar Radiation in Varying Weather Conditions for a Dynamic Simulation of the Solar Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Taehong Sung

    2015-07-01

    Full Text Available A mathematical model of hourly solar radiation with weather variability is proposed based on the simple sky model. The model uses a superposition of trigonometric functions with short and long periods. We investigate the effects of the model variables on the clearness (kD and the probability of persistence (POPD indices and also evaluate the proposed model for all of the kD-POPD weather classes. A simple solar organic Rankine cycle (SORC system with thermal storage is simulated using the actual weather conditions, and then, the results are compared with the simulation results using the proposed model and the simple sky model. The simulation results show that the proposed model provides more accurate system operation characteristics than the simple sky model.

  1. Working Fluid Stability in Large-Scale Organic Rankine Cycle-Units Using Siloxanes—Long-Term Experiences and Fluid Recycling

    National Research Council Canada - National Science Library

    Erhart, Tobias; Gölz, Jürgen; Eicker, Ursula; van den Broek, Martijn

    2016-01-01

    .... All presented fluid samples are analyzed via head space gas chromatography mass spectrometry (HS-GC-MS). Besides the siloxane composition, the influence of contaminants, such as mineral oil-based lubricants...

  2. Conversion of Low Quality Waste Heat to Electric Power with Small-Scale Organic Rankine Cycle (ORC) Engine/Generator Technology

    Science.gov (United States)

    2016-06-01

    simplified’ in the sense that it does not account for costs associated with financing (other than cost of money or discount rate) or taxes, or for...was completed in constant dollars (excluding inflation) per recommendations for non- financed projects in the BLCC model documentation and Handbook... startup costs. Labor & materials required to install (actual and projected for ‘typical’ installation) ElectraTherm, MUSE and deployment site

  3. Secondary education in the 1990s

    NARCIS (Netherlands)

    H.M. Bronneman-Helmers; L.J. Herweijer; H.M.G. Vogels

    2002-01-01

    Original title: Voortgezet onderwijs in de jaren negentig. Many changes and innovations have been set in motion in Dutch secondary education in recent years: the introduction of basic secondary education, increases in scale, profiles and the 'house of study' in the second phase of senior

  4. Quantitative evaluation of boron neutron capture therapy (BNCT) drugs for boron delivery and retention at subcellular scale resolution in human glioblastoma cells with imaging secondary ion mass spectrometry (SIMS)

    Science.gov (United States)

    Chandra, S.; Ahmad, T.; Barth, R. F.; Kabalka, G. W.

    2014-01-01

    Boron neutron capture therapy (BNCT) of cancer depends on the selective delivery of a sufficient number of boron-10 (10B) atoms to individual tumor cells. Cell killing results from the 10B (n, α)7Li neutron capture and fission reactions that occur if a sufficient number of 10B atoms are localized in the tumor cells. Intranuclear 10B localization enhances the efficiency of cell killing via damage to the DNA. The net cellular content of 10B atoms reflects both bound and free pools of boron in individual tumor cells. The assessment of these pools, delivered by a boron delivery agent, currently cannot be made at subcellular scale resolution by clinically applicable techniques such as PET and MRI. In this study, secondary ion mass spectrometry (SIMS) based imaging instrument, a CAMECA IMS 3f ion microscope, capable of 500 nm spatial resolution was employed. Cryogenically prepared cultured human T98G glioblastoma cells were evaluated for boron uptake and retention of two delivery agents. The first, L-p-boronophenylalanine (BPA), has been used clinically for BNCT of high grade gliomas, recurrent tumors of the head and neck region and melanomas. The second, a boron analogue of an unnatural amino acid, 1-amino-3-borono-cyclopentanecarboxylic acid (cis-ABCPC), has been studied in rodent glioma and melanoma models by quantification of boron in the nucleus and cytoplasm of individual tumor cells. The bound and free pools of boron were assessed by exposure of cells to boron-free nutrient medium. Both BPA and cis-ABCPC delivered almost 70% of the pool of boron in the free or loosely bound form to the nucleus and cytoplasm of human glioblastoma cells. This free pool of boron could be easily mobilized out of the cell and was in some sort of equilibrium with extracellular boron. In the case of BPA, the intracellular free pool of boron also was affected by the presence of phenylalanine in the nutrient medium. This suggests that it might be advantageous if patients were placed on a

  5. Quantitative evaluation of boron neutron capture therapy (BNCT) drugs for boron delivery and retention at subcellular-scale resolution in human glioblastoma cells with imaging secondary ion mass spectrometry (SIMS).

    Science.gov (United States)

    Chandra, S; Ahmad, T; Barth, R F; Kabalka, G W

    2014-06-01

    Boron neutron capture therapy (BNCT) of cancer depends on the selective delivery of a sufficient number of boron-10 ((10)B) atoms to individual tumour cells. Cell killing results from the (10)B (n, α)(7) Li neutron capture and fission reactions that occur if a sufficient number of (10)B atoms are localized in the tumour cells. Intranuclear (10)B localization enhances the efficiency of cell killing via damage to the DNA. The net cellular content of (10)B atoms reflects both bound and free pools of boron in individual tumour cells. The assessment of these pools, delivered by a boron delivery agent, currently cannot be made at subcellular-scale resolution by clinically applicable techniques such as positron emission tomography and magnetic resonance imaging. In this study, a secondary ion mass spectrometry based imaging instrument, a CAMECA IMS 3f ion microscope, capable of 500 nm spatial resolution was employed. Cryogenically prepared cultured human T98G glioblastoma cells were evaluated for boron uptake and retention of two delivery agents. The first, L-p-boronophenylalanine (BPA), has been used clinically for BNCT of high-grade gliomas, recurrent tumours of the head and neck region and melanomas. The second, a boron analogue of an unnatural amino acid, 1-amino-3-borono-cyclopentanecarboxylic acid (cis-ABCPC), has been studied in rodent glioma and melanoma models by quantification of boron in the nucleus and cytoplasm of individual tumour cells. The bound and free pools of boron were assessed by exposure of cells to boron-free nutrient medium. Both BPA and cis-ABCPC delivered almost 70% of the pool of boron in the free or loosely bound form to the nucleus and cytoplasm of human glioblastoma cells. This free pool of boron could be easily mobilized out of the cell and was in some sort of equilibrium with extracellular boron. In the case of BPA, the intracellular free pool of boron also was affected by the presence of phenylalanine in the nutrient medium. This

  6. Exergetic and environmental impact assessments of an integrated organic Rankine cycle with a biomass combustor for combined cooling, heating and power production

    Energy Technology Data Exchange (ETDEWEB)

    Al-Sulaiman, F.A. [Carleton Univ., Ottawa, ON (Canada). Dept. of Mechanical and Aerospace Engineering; Hamdullahpur, F. [Waterloo Univ., ON (Canada). Dept. of Mechanical and Mechatronics Engineering; Dincer, I. [Univ. of Ontario Inst. of Technology, Oshawa, ON (Canada). Faculty of Engineering and Applied Science

    2010-07-01

    A trigeneration thermal system produces cooling, heating and power from the same source. In trigeneration plants, waste heat is used for heating and cooling. In this paper, exergetic and environmental impact analyses of a trigeneration system based on an integrated organic Rankine cycle (ORC) with a biomass combustor were conducted. The analyses were extended to include electrical-power, cooling-cogeneration and heating-cogeneration cases. The objective was to understand the working phenomena of the proposed system, and identify and quantify the sources of the irreversibilities in the system associated with each component. The environmental impact of the proposed system was also quantified. The exergy efficiency, exergy destruction rate and carbon dioxide (CO{sub 2}) emissions were examined under the variations of pump inlet temperature and turbine inlet pressure. The results showed that exergy efficiency increased to 27 per cent when trigeneration was used as compared 11 per cent when the electrical power system was used. The main two sources of exergy destruction were the biomass combustor and the ORC evaporator. Emissions of CO{sub 2} were much higher in the case of the the electrical-power system compared to the trigeneration system. 11 refs., 1 tab., 8 figs.

  7. Estimation of performance of a high-speed boat by using the Rankine source method; Kosokutei no rankinsosuho ni yoru seino suitei ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Eguchi, T. [Mitsui Engineering and Shipbuilding Co. Ltd., Tokyo (Japan)

    1997-10-01

    This paper describes estimation of performance of a high-speed boat by using the Rankine source method. An orthogonal coordinate system is considered, which uses the center of a hull as the zero point, and is made dimensionless by using the hull length. The catamaran boat or the single hull boat being the subject of the discussion is supposed to have a transom stern, and to be sailing at a constant speed in the -X direction. A governing equation and a border condition were formulated using disturbance speed potential and X-direction speed differentiation. An inverse specular image was employed as a specular image system upon considering attitude change in the high-speed boat. As to the division of hull surface, the portions protruded above the static water surface were cut off from among the panel data of boat CAD. Considering a high speed condition in which the water surface is completely separated at the transom section, the water level at the transom section was supposed to be at the same height as at the rear end of the hull. Blow-out intensity at the water surface was derived in such a way that a CAD panel of the rear end of the hull is searched and wave height agrees with the height of the transom in the Z direction. A resistance curve may be obtained easily by using a personal computer. 4 refs., 8 figs.

  8. Ideal Point Design and Operation of CO2-Based Transcritical Rankine Cycle (CTRC System Based on High Utilization of Engine’s Waste Heats

    Directory of Open Access Journals (Sweden)

    Lingfeng Shi

    2017-10-01

    Full Text Available This research conducted a study specially to systematically analyze combined recovery of exhaust gas and engine coolant and related influence mechanism, including a detailed theoretical study and an assistant experimental study. In this research, CO2-based transcritical Rankine cycle (CTRC was used for fully combining the wastes heats. The main objective of theoretical research was to search an ‘ideal point’ of the recovery system and related influence mechanism, which was defined as operating condition of complete recovery of two waste heats. The theoretical methodology of this study could also provide a design reference for effective combined recovery of two or multiple waste heats in other fields. Based on a kW-class preheated CTRC prototype that was designed by the ‘ideal point’ method, an experimental study was conducted to verify combined utilization degree of two engine waste heats by the CTRC system. The operating results showed that the prototype can gain 44.4–49.8 kW and 22.7–26.7 kW heat absorption from exhaust gas and engine coolant, respectively. To direct practical operation, an experimental optimization work on the operating process was conducted for complete recovery of engine coolant exactly, which avoided deficient or excessive recovery.

  9. Thermo-Economic and Heat Transfer Optimization of Working-Fluid Mixtures in a Low-Temperature Organic Rankine Cycle System

    Directory of Open Access Journals (Sweden)

    Oyeniyi A. Oyewunmi

    2016-06-01

    Full Text Available In the present paper, we consider the employment of working-fluid mixtures in organic Rankine cycle (ORC systems with respect to thermodynamic and heat-transfer performance, component sizing and capital costs. The selected working-fluid mixtures promise reduced exergy losses due to their non-isothermal phase-change behaviour, and thus improved cycle efficiencies and power outputs over their respective pure-fluid components. A multi-objective cost-power optimization of a specific low-temperature ORC system (operating with geothermal water at 98 °C reveals that the use of working-fluid-mixtures does indeed show a thermodynamic improvement over the pure-fluids. At the same time, heat transfer and cost analyses, however, suggest that it also requires larger evaporators, condensers and expanders; thus, the resulting ORC systems are also associated with higher costs. In particular, 50% n-pentane + 50% n-hexane and 60% R-245fa + 40% R-227ea mixtures lead to the thermodynamically optimal cycles, whereas pure n-pentane and pure R-245fa have lower plant costs, both estimated as having ∼14% lower costs per unit power output compared to the thermodynamically optimal mixtures. These conclusions highlight the importance of using system cost minimization as a design objective for ORC plants.

  10. Thermodynamic Performance Analysis of a Biogas-Fuelled Micro-Gas Turbine with a Bottoming Organic Rankine Cycle for Sewage Sludge and Food Waste Treatment Plants

    Directory of Open Access Journals (Sweden)

    Sunhee Kim

    2017-02-01

    Full Text Available In the Republic of Korea, efficient biogas-fuelled power systems are needed to use the excess biogas that is currently burned due to a lack of suitable power technology. We examined the performance of a biogas-fuelled micro-gas turbine (MGT system and a bottoming organic Rankine cycle (ORC. The MGT provides robust operation with low-grade biogas, and the exhaust can be used for heating the biodigester. Similarly, the bottoming ORC generates additional power output with the exhaust gas. We selected a 1000-kW MGT for four co-digestion plants with 28,000-m3 capacity. A 150-kW ORC system was selected for the MGT exhaust gas. We analysed the effects of the system size, methane concentration, and ORC operating conditions. Based on the system performance, we analysed the annual performance of the MGT with a combined heat and power (CHP system, bottoming ORC, or both a bottoming ORC and CHP system. The annual net power outputs for each system were 7.4, 8.5, and 9.0 MWh per year, respectively.

  11. Analyzing the Performance of a Dual Loop Organic Rankine Cycle System for Waste Heat Recovery of a Heavy-Duty Compressed Natural Gas Engine

    Directory of Open Access Journals (Sweden)

    Baofeng Yao

    2014-11-01

    Full Text Available A dual loop organic Rankine cycle (DORC system is designed to recover waste heat from a heavy-duty compressed natural gas engine (CNGE, and the performance of the DORC–CNGE combined system is simulated and discussed. The DORC system includes high-temperature (HT and low-temperature (LT cycles. The HT cycle recovers energy from the exhaust gas emitted by the engine, whereas the LT cycle recovers energy from intake air, engine coolant, and the HT cycle working fluid in the preheater. The mathematical model of the system is established based on the first and second laws of thermodynamics. The characteristics of waste heat energy from the CNGE are calculated according to engine test data under various operating conditions. Moreover, the performance of the DORC–CNGE combined system is simulated and analyzed using R245fa as the working fluid. Results show that the maximum net power output and the maximum thermal efficiency of the DORC system are 29.37 kW and 10.81%, respectively, under the rated power output condition of the engine. Compared with the original CNG engine, the maximum power output increase ratio and the maximum brake specific fuel consumption improvement ratio are 33.73% and 25%, respectively, in the DORC–CNGE combined system.

  12. Studi Numerik Dua Dimensi Labyrinth Seal Turbin Uap Organic Rankine Cycle (ORC Type Straight-Through dengan Variasi Tekanan Inlet, Kecepatan Putaran Poros, Jarak Pitch, dan Tinggi Rongga

    Directory of Open Access Journals (Sweden)

    Fungki Setyo Yulianto

    2013-03-01

    Full Text Available ORC (Organic Rankine Cycle merupakan salah satu sistem pembangkit tenaga yang mampu memanfaatkan waste energy dengan menggunakan fluida organik yang mampu menguap pada temperatur dan tekanan rendah. Salah satu komponen utama pada sistem ORC adalah Turbin. Untuk mendapatkan efisiensi yang maksimal,  kebocoran fluida pada turbin uap harus di minimalisir. Untuk itulah di perlukan penggunaan labyrinth seal untuk mengurai kebocoran fluida R123 pada turbin uap ORC. Pada dunia Industri jenis labyrinth seal sangat banyak sekali, salah satunya adalah labyrinth seal tipe Straight-Through. Penelitian ini dilakukan dengan metode numerik (CFD software Fluent. Penelitian ini menggunakan variasi tekanan inlet yaitu 5, 10 dan 15 bar, putaran poros 0, 1500 dan 3000 rpm, panjang pitch 4 mm, 6 mm, 8 mm, 10 mm, serta tinggi rongga 3,415 mm, 3,915 mm dan 5,915 mm. Simulasi menggunakan model turbulensi k-ε RNG. Pada variasi tekanan inlet laju kebocoran paling besar terjadi pada tekanan 15 bar. Pada variasi putaran poros laju kebocoran terjadi berubah secara signifikan pada setiap variasi. Pada variasi tinggi rongga laju kebocoran paling kecil terjadi pada tinggi rongga 3,415 mm. Pada variasi panjang pitch, laju kebocoran paling kecil terjadi pada panjang pitch 10 mm.

  13. Geometry Analysis and Effect of Turbulence Model on the Radial Rotor Turbo-Expander Design for Small Organic Rankine Cycle System

    Directory of Open Access Journals (Sweden)

    Maulana Arifin

    2015-07-01

    Full Text Available Organic Rankine Cycle (ORC is one of the most promising technology for small electric power generations. The geometry analysis and the effect of turbulence model on the radial turbo-expanders design for small ORC power generation systems were discussed in this paper. The rotor blades and performance were calculated using several working fluids such as R134a, R143a, R245fa, n-Pentane, and R123. Subsequently, a numerical study was carried out in the fluid flow area with R134a and R123 as the working fluids. Analyses were performed using Computational Fluid Dynamics (CFD ANSYS Multiphysics on two real gas models, with the k-epsilon and SST (shear stress transport turbulence models. The result shows the distribution of Mach number, pressure, velocity and temperature along the rotor blade of the radial turbo-expanders and estimation of performance at various operating conditions. The operating conditions are as follow: 250,000 grid mesh flow area, real gas model SST at steady state condition, 0.4 kg/s of mass flow rate, 15,000 rpm rotor speed, 5 bar inlet pressure, and 373K inlet temperature. By using those conditions, CFD analysis shows that the turbo-expander able to produce 6.7 kW and 5.5 kW of power when using R134a and R123, respectively.

  14. Milestone Report #2: Direct Evaporator Leak and Flammability Analysis Modifications and Optimization of the Organic Rankine Cycle to Improve the Recovery of Waste Heat

    Energy Technology Data Exchange (ETDEWEB)

    Guillen, Donna Post [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2013-09-01

    The direct evaporator is a simplified heat exchange system for an Organic Rankine Cycle (ORC) that generates electricity from a gas turbine exhaust stream. Typically, the heat of the exhaust stream is transferred indirectly to the ORC by means of an intermediate thermal oil loop. In this project, the goal is to design a direct evaporator where the working fluid is evaporated in the exhaust gas heat exchanger. By eliminating one of the heat exchangers and the intermediate oil loop, the overall ORC system cost can be reduced by approximately 15%. However, placing a heat exchanger operating with a flammable hydrocarbon working fluid directly in the hot exhaust gas stream presents potential safety risks. The purpose of the analyses presented in this report is to assess the flammability of the selected working fluid in the hot exhaust gas stream stemming from a potential leak in the evaporator. Ignition delay time for cyclopentane at temperatures and pressure corresponding to direct evaporator operation was obtained for several equivalence ratios. Results of a computational fluid dynamic analysis of a pinhole leak scenario are given.

  15. Modeling and Experimental Validation of a Volumetric Expander Suitable for Waste Heat Recovery from an Automotive Internal Combustion Engine Using an Organic Rankine Cycle with Ethanol

    Directory of Open Access Journals (Sweden)

    José Galindo

    2016-04-01

    Full Text Available Waste heat recovery (WHR in exhaust gas flow of automotive engines has proved to be a useful path to increase the overall efficiency of internal combustion engines (ICE. Recovery potentials of up to 7% are shown in several works in the literature. However, most of them are theoretical estimations. Some present results from prototypes fed by steady flows generated in an auxiliary gas tank and not with actual engine exhaust gases. This paper deals with the modeling and experimental validation of an organic Rankine cycle (ORC with a swash-plate expander integrated in a 2 L turbocharged petrol engine using ethanol as working fluid. A global simulation model of the ORC was developed with a maximum difference of 5%, validated with experimental results. Considering the swash-plate as the main limiting factor, an additional specific submodel was implemented to model the physical phenomena in this element. This model allows simulating the fluid dynamic behavior of the swash-plate expander using a 0D model (Amesim. Differences up to 10.5% between tests and model results were found.

  16. Thermoeconomic Evaluation of Modular Organic Rankine Cycles for Waste Heat Recovery over a Broad Range of Heat Source Temperatures and Capacities

    Directory of Open Access Journals (Sweden)

    Markus Preißinger

    2017-02-01

    Full Text Available Industrial waste heat recovery by means of an Organic Rankine Cycle (ORC can contribute to the reduction of CO2 emissions from industries. Before market penetration, high efficiency modular concepts have to be developed to achieve appropriate economic value for industrial decision makers. This paper aims to investigate modularly designed ORC systems from a thermoeconomic point of view. The main goal is a recommendation for a suitable chemical class of working fluids, preferable ORC design and a range of heat source temperatures and thermal capacities in which modular ORCs can be economically feasible. For this purpose, a thermoeconomic model has been developed which is based on size and complexity parameters of the ORC components. Special emphasis has been laid on the turbine model. The paper reveals that alkylbenzenes lead to higher exergetic efficiencies compared to alkanes and siloxanes. However, based on the thermoeconomic model, the payback periods of the chemical classes are almost identical. With the ORC design, the developed model and the boundary conditions of this study, hexamethyldisiloxane is a suitable working fluid and leads to a payback period of less than 5 years for a heat source temperature of 400 to 600 °C and a mass flow rate of the gaseous waste heat stream of more than 4 kg/s.

  17. A quantitative risk-assessment system (QR-AS) evaluating operation safety of Organic Rankine Cycle using flammable mixture working fluid.

    Science.gov (United States)

    Tian, Hua; Wang, Xueying; Shu, Gequn; Wu, Mingqiang; Yan, Nanhua; Ma, Xiaonan

    2017-09-15

    Mixture of hydrocarbon and carbon dioxide shows excellent cycle performance in Organic Rankine Cycle (ORC) used for engine waste heat recovery, but the unavoidable leakage in practical application is a threat for safety due to its flammability. In this work, a quantitative risk assessment system (QR-AS) is established aiming at providing a general method of risk assessment for flammable working fluid leakage. The QR-AS covers three main aspects: analysis of concentration distribution based on CFD simulations, explosive risk assessment based on the TNT equivalent method and risk mitigation based on evaluation results. A typical case of propane/carbon dioxide mixture leaking from ORC is investigated to illustrate the application of QR-AS. According to the assessment results, proper ventilation speed, safe mixture ratio and location of gas-detecting devices have been proposed to guarantee the security in case of leakage. The results revealed that this presented QR-AS was reliable for the practical application and the evaluation results could provide valuable guidance for the design of mitigation measures to improve the safe performance of ORC system. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. A proposal for the modular integration of the renewable energy sources, via hydrogen, and the Rankine power cycle; Una propuesta de integracion modular de las fuentes de energia renovables, via hidrogeno, y el ciclo de potencia Rankine

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Dirzo, Rafael

    2004-07-01

    This thesis synthesizes the state-of-the-art of the modular integration of the renewable energy sources and the Ranking power cycle. This is possible to obtain due to the development of the hydrogen production technologies and with it the chemical storage of the energies solar, Aeolian (wind) and tidal, among others. The purpose of this thesis is the assessment of hydrogen as fuel, its obtaining through the breaking of the water molecule using the renewable energies and the thermodynamic analysis of two prototypes for its energy conversion into electricity and power, voltage and fixed frequency: the first one at laboratory scale of 800 W and the second one, on industrial scale of 1 GW of power. Included here is the synthesis of the increasing bibliography on the development of the hydrogen technologies and the renewable energies, passing through the mass and energy balance in the power cycles until proposing, at the level of Process Flow Charts of the results of the proposed prototypes. The products show the possibility of constructing and operating the experimental prototype, whereas the thermodynamic analysis suggests that the industrial prototype is viable. The economic analysis of both proposals is part of a doctorate project in process. [Spanish] Esta tesis sintetiza el estado del arte de la integracion modular de las fuentes de energia renovables y el ciclo de potencia Ranking. Esto es posible lograrlo debido al desarrollo de las tecnologias de produccion de hidrogeno y con ello el almacenamiento quimico de las energias solar, eolica y maremotriz, entre otras. Es objetivo de esta tesis la valoracion del hidrogeno como combustible, su obtencion a traves del rompimiento de la molecula del agua utilizando las energias renovables y el analisis termodinamico de dos prototipo para su conversion energetica en electricidad a potencia, voltaje y frecuencia fijos: el primero a escala de laboratorio de 800 W y el segundo, a escala industrial de 1 GW de potencia. Se

  19. Association Between Change in Body Mass Index, Unified Parkinson's Disease Rating Scale Scores, and Survival Among Persons With Parkinson Disease: Secondary Analysis of Longitudinal Data From NINDS Exploratory Trials in Parkinson Disease Long-term Study 1.

    Science.gov (United States)

    Wills, Anne-Marie A; Pérez, Adriana; Wang, Jue; Su, Xiao; Morgan, John; Rajan, Suja S; Leehey, Maureen A; Pontone, Gregory M; Chou, Kelvin L; Umeh, Chizoba; Mari, Zoltan; Boyd, James

    2016-03-01

    Greater body mass index (BMI, calculated as weight in kilograms divided by height in meters squared) is associated with improved survival among persons with Huntington disease or amyotrophic lateral sclerosis. Weight loss is common among persons with Parkinson disease (PD) and is associated with worse quality of life. To explore the association between change in BMI, Unified Parkinson's Disease Rating Scale (UPDRS) motor and total scores, and survival among persons with PD and to test whether there is a positive association between BMI at randomization and survival. Secondary analysis (from May 27, 2014, to October 13, 2015) of longitudinal data (3-6 years) from 1673 participants who started the National Institute of Neurological Disorders and Stroke Exploratory Trials in PD Long-term Study-1 (NET-PD LS-1). This was a double-blind randomized placebo-controlled clinical trial of creatine monohydrate (10 g/d) that was performed at 45 sites throughout the United States and Canada. Participants with early (within 5 years of diagnosis) and treated (receiving dopaminergic therapy) PD were enrolled from March 2007 to May 2010 and followed up until September 2013. Change across time in motor UPDRS score, change across time in total UPDRS score, and time to death. Generalized linear mixed models were used to estimate the effect of BMI on the change in motor and total UPDRS scores after controlling for covariates. Survival was analyzed using Cox proportional hazards models of time to death. A participant's BMI was measured at randomization, and BMI trajectory groups were classified according to whether participants experienced weight loss ("decreasing BMI"), weight stability ("stable BMI"), or weight gain ("increasing BMI") during the study. Of the 1673 participants (mean [SD] age, 61.7 [9.6] years; 1074 [64.2%] were male), 158 (9.4%) experienced weight loss (decreasing BMI), whereas 233 (13.9%) experienced weight gain (increasing BMI). After adjusting for covariates, we

  20. Hyperaldosteronism - primary and secondary

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/000330.htm Hyperaldosteronism - primary and secondary To use the sharing features on ... hormone aldosterone into the blood. Hyperaldosteronism can be primary or secondary. Causes Primary hyperaldosteronism is due to ...

  1. Preliminary design of seawater and brackish water reverse osmosis desalination systems driven by low-temperature solar organic Rankine cycles (ORC)

    Energy Technology Data Exchange (ETDEWEB)

    Delgado-Torres, Agustin M. [Dpto. Fisica Fundamental y Experimental, Electronica y Sistemas, Escuela Tecnica Superior de Ingenieria Civil e Industrial, Universidad de La Laguna (ULL), Avda. Astrofisico Francisco Sanchez s/n. 38206 La Laguna (Tenerife) (Spain); Garcia-Rodriguez, Lourdes [Dpto. Ingenieria Energetica, Universidad de Sevilla Escuela Tecnica Superior de Ingenieros, Camino de los Descubrimientos, s/n 41092 Sevilla (Spain)

    2010-12-15

    In this paper, the coupling between the low-temperature solar organic Rankine cycle (ORC) and seawater and brackish water reverse osmosis desalination units has been carried out. Four substances have been considered as working fluids of the solar cycle (butane, isopentane, R245fa and R245ca). With these four fluids the volumetric flow of fresh water produced per unit of aperture area of stationary solar collector has been calculated. The former has been made with the optimized direct vapour generation (DVG) configuration and heat transfer fluid (HTF) configuration of the solar ORC. In the first one (DVG), working fluid of the ORC is directly heated inside the absorber of the solar collector. In the second one (HTF), a fluid different than the working fluid of the ORC (water in this paper) is heated without phase change inside the absorber of the solar collector. Once this fluid has been heated it is carried towards a heat exchanger where it is cooled. Thermal energy delivered in this cooling process is transferred to the working fluid of the ORC. Influence of condensation temperature of the ORC and regeneration's process effectiveness over productivity of the system has also been analysed. Finally, parameters of several preliminary designs of the low-temperature solar thermal driven RO desalination are supplied. R245fa is chosen as working fluid of the ORC in these preliminary designs. The information of the proposed preliminary designs can also be used, i.e., for the assessment of the use of thermal energy rejected by the solar cycle. Overall analysis of the efficiency of the solar thermal driven RO desalination technology is given with the results presented in this paper and the results obtained with the medium temperature solar thermal RO desalination system presented by the authors in previous papers. This work has been carried out within the framework of the OSMOSOL and POWERSOL projects. (author)

  2. Symptom clusters for revising scale membership in the analysis of prostate cancer patient reported outcome measures: a secondary data analysis of the Medical Research Council RT01 trial (ISCRTN47772397).

    Science.gov (United States)

    Lemanska, Agnieszka; Chen, Tao; Dearnaley, David P; Jena, Rajesh; Sydes, Matthew R; Faithfull, Sara

    2017-08-01

    To investigate the role of symptom clusters in the analysis and utilisation of patient reported outcome measures (PROMs) for data modelling and clinical practice. To compare symptom clusters with scales, and to explore their value in PROMs interpretation and symptom management. A dataset called RT01 (ISCRTN47772397) of 843 prostate cancer patients was used. PROMs were reported with the University of California, Los Angeles Prostate Cancer Index (UCLA-PCI). Symptom clusters were explored with hierarchical cluster analysis (HCA) and average linkage method (correlation > 0.6). The reliability of the Urinary Function Scale was evaluated with Cronbach's Alpha. The strength of the relationship between the items was investigated with Spearman's correlation. Predictive accuracy of the clusters was compared to the scales by receiver operating characteristic (ROC) analysis. Presence of urinary symptoms at 3 years measured with the late effects on normal tissue: subjective, objective, management tool (LENT/SOM) was an endpoint. Two symptom clusters were identified (urinary cluster and sexual cluster). The grouping of symptom clusters was different than UCLA-PCI Scales. Two items of the urinary function scales ("number of pads" and "urinary leak interfering with sex") were excluded from the urinary cluster. The correlation with the other items in the scale ranged from 0.20 to 0.21 and 0.31 to 0.39, respectively. Cronbach's Alpha showed low correlation of those items with the Urinary Function Scale (0.14-0.36 and 0.33-0.44, respectively). All urinary function scale items were subject to a ceiling effect. Clusters had better predictive accuracy, AUC = 0.70 -0.65, while scales AUC = 0.67-0.61. This study adds to the knowledge on how cluster analysis can be applied for the interpretation and utilisation of PROMs. We conclude that multiple-item scales should be evaluated and that symptom clusters provide a study-specific approach for modelling and interpretation of

  3. Análise teórica da recuperação de calor para geração de energia em indústrias de cimento e cal utilizando o ciclo de Rankine orgânico

    Directory of Open Access Journals (Sweden)

    Ricardo Carrasco Carpio

    2015-06-01

    Full Text Available O presente trabalho consiste em uma apresentação do estado da arte do Ciclo Rankine Orgânico, um ciclo termodinâmico que usa um fluido orgânico como fluido de trabalho e que pode ser usado para recuperação de calor rejeitado em processos industriais, gerando assim energia elétrica para abastecer a própria indústria, o que consequentemente causa uma redução no custo de produção da empresa. São apresentados alguns fluidos orgânicos e alguns de seus parâmetros termodinâmicos.Palavras-chave: Cogeração. Ciclo Rankine Orgânico. Fluidos de Trabalho.ABSTRACTTheoretical analysis of heat recovery for power generation in cement and lime industries using the organic Rankine cycleThis work aims to present the state of the art of the Organic Rankine Cycle, a thermodynamic cycle that uses an organic fluid as a working fluid that can be used to recover the rejected heat in industrial processes, thus generating electricity to supply industry itself, which causes a reduction in the production cost of the company. It also presents some organic fluids and some of their thermodynamic parameters.Keywords: Cogeneration. Organic Rankine Cycle. Working Fluids.

  4. Performance Analysis of an Evaporator for a Diesel Engine–Organic Rankine Cycle (ORC Combined System and Influence of Pressure Drop on the Diesel Engine Operating Characteristics

    Directory of Open Access Journals (Sweden)

    Chen Bei

    2015-06-01

    Full Text Available The main purpose of this research is to analyze the performance of an evaporator for the organic Rankine cycle (ORC system and discuss the influence of the evaporator on the operating characteristics of diesel engine. A simulation model of fin-and-tube evaporator of the ORC system is established by using Fluent software. Then, the flow and heat transfer characteristics of the exhaust at the evaporator shell side are obtained, and then the performance of the fin-and-tube evaporator of the ORC system is analyzed based on the field synergy principle. The field synergy angle (β is the intersection angle between the velocity vector and the temperature gradient. When the absolute values of velocity and temperature gradient are constant and β < 90°, heat transfer enhancement can be achieved with the decrease of the β. When the absolute values of velocity and temperature gradient are constant and β >90°, heat transfer enhancement can be achieved with the increase of the β. Subsequently, the influence of the evaporator of the ORC system on diesel engine performance is studied. A simulation model of the diesel engine is built by using GT–Power software under various operating conditions, and the variation tendency of engine power, torque, and brake specific fuel consumption (BSFC are obtained. The variation tendency of the power output and BSFC of diesel engine–ORC combined system are obtained when the evaporation pressure ranges from 1.0 MPa to 3.5 MPa. Results show that the field synergy effect for the areas among the tube bundles of the evaporator main body and the field synergy effect for the areas among the fins on the windward side are satisfactory. However, the field synergy effect in the areas among the fins on the leeward side is weak. As a result of the pressure drop caused by the evaporator of the ORC system, the diesel engine power and torque decreases slightly, whereas the BSFC increases slightly with the increase of exhaust back

  5. Methods of increasing net work output of organic Rankine cycles for low-grade waste heat recovery with a detailed analysis using a zeotropic working fluid mixture and scroll expander

    Science.gov (United States)

    Woodland, Brandon Jay

    An organic Rankine cycle (ORC) is a thermodynamic cycle that is well-suited for waste heat recovery. It is generally employed for waste heat with temperatures in the range of 80 °C -- 300 °C. When the application is strictly to convert waste heat into work, thermal efficiency is not recommended as a key performance metric. In such an application, maximization of the net power output should be the objective rather than maximization of the thermal efficiency. Two alternative cycle configurations that can increase the net power produced from a heat source with a given temperature and flow rate are proposed and analyzed. These cycle configurations are 1) an ORC with two-phase flash expansion and 2) an ORC with a zeotropic working fluid mixture (ZRC). A design-stage ORC model is presented for consistent comparison of multiple ORC configurations. The finite capacity of the heat source and heat sink fluids is a key consideration in this model. Of all working fluids studied for the baseline ORC, R134a and R245fa yield the highest net power output from a given heat source. Results of the design-stage model indicate that the ORC with two-phase flash expansion offers the most improvement over the baseline ORC. However, the level of improvement that could be achieved in practice is highly uncertain due to the requirement of highly efficient two-phase expansion. The ZRC shows improvement over the baseline as long as the condenser fan power requirement is not negligible. At the highest estimated condenser fan power, the ZRC shows the most improvement, while the ORC with flash expansion is no longer beneficial. The ZRC was selected for detailed study because it does not require two-phase expansion. An experimental test rig was used to evaluate baseline ORC performance with R134a and with R245fa. The ZRC was tested on the same rig with a mixture of 62.5% R134a and 37.5% R245fa. The tested expander is a minimally-modified, of-the-shelf automotive scroll compressor. The high

  6. Gifted Secondary School Students

    Science.gov (United States)

    Brigandi, Carla B.; Siegle, Del; Weiner, Jennie M.; Gubbins, E. Jean; Little, Catherine A.

    2016-01-01

    Grounded in the Enrichment Triad and Achievement Orientation Models, this qualitative case study builds understanding of the relationship between participation in Type III Enrichment and the achievement orientation attitude of goal valuation in gifted secondary school students. Participants included 10 gifted secondary school students, their…

  7. Evaluation of a Short Version of the Illinois Loneliness and Social Satisfaction Scale in a Sample of Students with and without Special Educational Needs--An Empirical Study with Primary and Secondary Students in Austria

    Science.gov (United States)

    Schwab, Susanne

    2015-01-01

    The first aim of this study was to evaluate the appropriateness of a short version of the Illinois Loneliness and Social Satisfaction Scale with children with special educational needs. The second aim was to explore loneliness in relation to self-perceived social integration, school well-being and the social self-concept of students from primary…

  8. Secondary and tertiary hyperparathyroidism.

    Science.gov (United States)

    Jamal, Sophie A; Miller, Paul D

    2013-01-01

    We reviewed the etiology and management of secondary and tertiary hyperparathyroidism. Secondary hyperparathyroidism is characterized by an increase in parathyroid hormone (PTH) that is appropriate and in response to a stimulus, most commonly low serum calcium. In secondary hyperparathyroidism, the serum calcium is normal and the PTH level is elevated. Tertiary hyperparathyroidism is characterized by excessive secretion of PTH after longstanding secondary hyperparathyroidism, in which hypercalcemia has ensued. Tertiary hyperparathyroidism typically occurs in men and women with chronic kidney disease usually after kidney transplant. The etiology and treatment of secondary hyperparathyroidism is relatively straightforward whereas data on the management of tertiary hyperparathyroidism is limited to a few small trials with short follow-up. Copyright © 2013 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.

  9. Secondary Traumatic Stress

    Directory of Open Access Journals (Sweden)

    Ayla Kahil

    2018-03-01

    Full Text Available Traumatic events do not only affect the person who was directly exposed to the incident, but they might also lead to some reactions on people with whom they interact. It is argued that, reactions given to a traumatic event by being exposed to the incident either primarily or secondarily, resemble each other. While in primary exposure the perceived threat is subjective, in secondary exposure the threat belongs to the person one interacts with. Secondary exposition to trauma may lead to re-experiencing, avoidance, and increased arousal symptoms as well as impairment in daily functioning. Briefly, secondary exposition to a traumatic incident induces parallel reactions as in those who are primarily exposed. In addition to these, taking specific precautions help decreasing the negative effects of secondary traumatic stress. This review focuses on the secondary traumatic stress and secondary traumatic stress disorder of workers who offer service in relief operations. For this aim, related theoretical concepts along with the literature studies are presented and information regarding ways of coping with the negative effects of secondary traumatization is discussed.

  10. Teaching secondary mathematics

    CERN Document Server

    Rock, David

    2013-01-01

    Solidly grounded in up-to-date research, theory and technology,?Teaching Secondary Mathematics?is a practical, student-friendly, and popular text for secondary mathematics methods courses. It provides clear and useful approaches for mathematics teachers, and shows how concepts typically found in a secondary mathematics curriculum can be taught in a positive and encouraging way. The thoroughly revised fourth edition combines this pragmatic approach with truly innovative and integrated technology content throughout. Synthesized content between the book and comprehensive companion websi

  11. Developing a Scale for Learner Autonomy Support

    Science.gov (United States)

    Oguz, Aytunga

    2013-01-01

    The aim of the present study is to develop a scale to determine how necessary the primary and secondary school teachers view the learner autonomy support behaviours and how much they perform these behaviours. The study group was composed of 324 primary and secondary school teachers. The process of developing the scale involved a literature scan,…

  12. [Secondary chondrosarcoma: radiopathological correlation].

    Science.gov (United States)

    Lozano Martínez, G A; Llauger Rosselló, J

    2015-01-01

    Chondrosarcomas are malignant bone tumors originating in cartilage. Chondrosarcoma is the third most common malignant bone tumor after multiple myeloma and osteosarcoma. About 75% of chondrosarcomas are primary lesions. The remaining 25% belong to special categories such as histologic variants and secondary forms. A secondary chondrosarcoma is one that appears in a pre-existing benign chondral lesion; the different types of secondary chondrosarcomas include solitary osteochondroma, multiple osteochondromatosis, enchondroma, the different types of enchondromatosis, and primary synovial chondromatosis. The incidence of this malignant transformation varies widely in function of the type of lesion. In this article, we discuss and illustrate the different types of secondary chondrosarcomas, placing special emphasis on the imaging findings that should alert to these lesions and give radiologists a key role in the diagnosis, management, and follow-up of these patients. Copyright © 2013 SERAM. Published by Elsevier España, S.L.U. All rights reserved.

  13. Radioactive demonstration of final mineralized waste forms for Hanford waste treatment plant secondary waste (WTP-SW) by fluidized bed steam reforming (FBSR) using the bench scale reformer platform

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Burket, P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Cozzi, A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Daniel, G. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Jantzen, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Missimer, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2014-08-01

    The U.S. Department of Energy’s Office of River Protection (ORP) is responsible for the retrieval, treatment, immobilization, and disposal of Hanford’s tank waste. Currently there are approximately 56 million gallons of highly radioactive mixed wastes awaiting treatment. A key aspect of the River Protection Project (RPP) cleanup mission is to construct and operate the Waste Treatment and Immobilization Plant (WTP). The WTP will separate the tank waste into high-level and low-activity waste (LAW) fractions, both of which will subsequently be vitrified. The projected throughput capacity of the WTP LAW Vitrification Facility is insufficient to complete the RPP mission in the time frame required by the Hanford Federal Facility Agreement and Consent Order, also known as the Tri-Party Agreement (TPA), i.e. December 31, 2047. Therefore, Supplemental Treatment is required both to meet the TPA treatment requirements as well as to more cost effectively complete the tank waste treatment mission. In addition, the WTP LAW vitrification facility off-gas condensate known as WTP Secondary Waste (WTP-SW) will be generated and enriched in volatile components such as 137Cs, 129I, 99Tc, Cl, F, and SO4 that volatilize at the vitrification temperature of 1150°C in the absence of a continuous cold cap (that could minimize volatilization). The current waste disposal path for the WTP-SW is to process it through the Effluent Treatment Facility (ETF). Fluidized Bed Steam Reforming (FBSR) is being considered for immobilization of the ETF concentrate that would be generated by processing the WTP-SW. The focus of this current report is the WTP-SW.

  14. Secondary metabolites from Ganoderma.

    Science.gov (United States)

    Baby, Sabulal; Johnson, Anil John; Govindan, Balaji

    2015-06-01

    Ganoderma is a genus of medicinal mushrooms. This review deals with secondary metabolites isolated from Ganoderma and their biological significance. Phytochemical studies over the last 40years led to the isolation of 431 secondary metabolites from various Ganoderma species. The major secondary compounds isolated are (a) C30 lanostanes (ganoderic acids), (b) C30 lanostanes (aldehydes, alcohols, esters, glycosides, lactones, ketones), (c) C27 lanostanes (lucidenic acids), (d) C27 lanostanes (alcohols, lactones, esters), (e) C24, C25 lanostanes (f) C30 pentacyclic triterpenes, (g) meroterpenoids, (h) farnesyl hydroquinones (meroterpenoids), (i) C15 sesquiterpenoids, (j) steroids, (k) alkaloids, (l) prenyl hydroquinone (m) benzofurans, (n) benzopyran-4-one derivatives and (o) benzenoid derivatives. Ganoderma lucidum is the species extensively studied for its secondary metabolites and biological activities. Ganoderma applanatum, Ganoderma colossum, Ganoderma sinense, Ganoderma cochlear, Ganoderma tsugae, Ganoderma amboinense, Ganoderma orbiforme, Ganoderma resinaceum, Ganoderma hainanense, Ganoderma concinna, Ganoderma pfeifferi, Ganoderma neo-japonicum, Ganoderma tropicum, Ganoderma australe, Ganoderma carnosum, Ganoderma fornicatum, Ganoderma lipsiense (synonym G. applanatum), Ganoderma mastoporum, Ganoderma theaecolum, Ganoderma boninense, Ganoderma capense and Ganoderma annulare are the other Ganoderma species subjected to phytochemical studies. Further phytochemical studies on Ganoderma could lead to the discovery of hitherto unknown biologically active secondary metabolites. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Post-secondary Education

    Science.gov (United States)

    Weathersby, George B.

    1976-01-01

    Concepts and quantitative tools of economics and sociology are applied to the definition of students' demand for post secondary education for several purposes including an analysis of the characteristics of young adults enrolled in colleges. Studies on the effects of policy instruments used to affect changes in demand are considered. (Author/AM)

  16. Suicide among Secondary Students.

    Science.gov (United States)

    Coder, Tamara L.; And Others

    1991-01-01

    Investigated incidence of adolescent suicide in Kansas and assessed prevention guidelines and services dealing with adolescent suicide, and perceived needs of Kansas secondary school counselors in the area of teenage suicide. Findings from 484 school counselors indicated increase in suicide rates with age and need for suicide prevention programing…

  17. Cosmetology. Secondary Curriculum Guide.

    Science.gov (United States)

    Moye, Michael D.; And Others

    This curriculum guide is designed to offer guidelines along with supporting resources and teaching ideas from which the local secondary instructor can extract a cosmetology curriculum that meets local needs. Following an outline of the philosophy and goals underlying state and local vocational education programs in Georgia, the purpose and…

  18. Secondary Syphilitic Lesions

    Science.gov (United States)

    Baughn, Robert E.; Musher, Daniel M.

    2005-01-01

    An important theme that emerges from all early historical accounts is that in addition to the decreased virulence of Treponema pallidum, the incidence of secondary syphilis has decreased drastically over the past three centuries. Even in the early 20th century, most syphilologists were of the opinion that the disease had undergone changes in its manifestations and that they were dealing with an attenuated form of the spirochete. Such opinions were based primarily on the observations that violent cutaneous reactions and fatalities associated with the secondary stage had become extremely rare. The rate of primary and secondary syphilis in the United States increased in 2002 for the second consecutive year. After a decade-long decline that led to an all-time low in 2000, the recent trend is attributable, to a large extent, by a increase in reported syphilis cases among men, particularly homosexual and bisexual men having sex with men. The present review addresses the clinical and diagnostic criteria for the recognition of secondary syphilis, the clinical course and manifestations of the disease if allowed to proceed past the primary stage of disease in untreated individuals, and the treatment for this stage of the disease. PMID:15653827

  19. Dynamics of secondary forests

    NARCIS (Netherlands)

    Breugel, van M.

    2007-01-01

    The succession of tropical secondary forests on abandoned agricultural fields has been studied since long, most often by comparing stands of different age since abandonment. These so-called chronosequence studies have yielded much insight in general patterns of succession and the constraints and

  20. Perfectionism among Turkish Secondary Students

    Directory of Open Access Journals (Sweden)

    Fatih Camadan

    2012-12-01

    Full Text Available The aim of this study was to analyze perfectionism among Turkish secondary school students. Perfectionism was compared according to the some variables like academic achievement, type of school, field (Quantitative, Verbal and Equally Weighted and gender. The study was performed with271 female and 320 male students. In this study Frost Multidimentional Perfectionism Scale (FMPS adapted into Turkish by Özbay and Mısırlı-Taşdemir (2003, was used. At the end of the study, in all subscales of perfectionism scale, there was significant variation according to student’s academic success levels. There was significant variation according to the school types in all subscales except Personal Standards subscale. While there was significant variation according to the field, in Parental Criticism and Concern over Mistakes subscales; according to gender, there was significant variation only in Doubt about Actions subscale. To not acceptnonperfect situations while trying to reach a goal may cause that students have procrastination behaviors and more anxiety. Therefore, their academic achievement may be affected negatively. With individual and group psychological counseling to perfectionist students can help them to notice their characteristics well and determine realistic goal. In this way, their academic achievement can be contributed positively

  1. Potassium Secondary Batteries.

    Science.gov (United States)

    Eftekhari, Ali; Jian, Zelang; Ji, Xiulei

    2017-02-08

    Potassium may exhibit advantages over lithium or sodium as a charge carrier in rechargeable batteries. Analogues of Prussian blue can provide millions of cyclic voltammetric cycles in aqueous electrolyte. Potassium intercalation chemistry has recently been demonstrated compatible with both graphite and nongraphitic carbons. In addition to potassium-ion batteries, potassium-O2 (or -air) and potassium-sulfur batteries are emerging. Additionally, aqueous potassium-ion batteries also exhibit high reversibility and long cycling life. Because of potentially low cost, availability of basic materials, and intriguing electrochemical behaviors, this new class of secondary batteries is attracting much attention. This mini-review summarizes the current status, opportunities, and future challenges of potassium secondary batteries.

  2. Secondary victims of rape

    DEFF Research Database (Denmark)

    Christiansen, Dorte Mølgaard; Bak, Rikke; Elklit, Ask

    2012-01-01

    Rape is often a very traumatic experience, which affects not only the primary victim (PV) but also his/her significant others. Studies on secondary victims of rape are few and have almost exclusively studied male partners of female rape victims. This study examined the impact of rape on 107...... secondary victims, including family members, partners, and friends of male and female rape victims. We found that many respondents found it difficult to support the PV and that their relationship with the PV was often affected by the assault. Furthermore, the sample showed significant levels...... of social support for the respondent, and feeling let down by others. The respondents were generally interested in friend-, family-, and partner-focused interventions, particularly in receiving education about how best to support a rape victim...

  3. Scale Construction: Motivation and Relationship Scale in Education

    Directory of Open Access Journals (Sweden)

    Yunus Emre Demir

    2016-01-01

    Full Text Available The aim of this study is to analyze the validity and reliability of the Turkish version of Motivation and Relationship Scale (MRS, (Raufelder , Drury , Jagenow , Hoferichter & Bukowski , 2013.Participants were 526 students of secondary school. The results of confirmatory factor analysis described that the 21 items loaded three factor and the three-dimensional model was well fit (x2= 640.04, sd= 185, RMSEA= .068, NNFI= .90, CFI = .91, IFI=.91,SRMR=079, GFI= .90,AGFI=.87. Overall findings demonstrated that this scale is a valid and indicates that the adapted MRS is a valid instrument for measuring secondary school children’s motivation in Turkey.

  4. SECONDARY AORTODUODENAL FISTULA

    Directory of Open Access Journals (Sweden)

    M. A. Mohammadzade

    2007-07-01

    Full Text Available "nSecondary aortoenteric fistula (SAF is an uncommon but very important complication of abdominal aortic reconstruction. The complication often occurs months to years after aortic surgery. The clinical manifestation of the aortoenteric fistula is always upper gastrointestinal bleeding. Treatment of the disease is early surgical intervention. If operative treatment is not performed promptly, the mortality is high. We present a case of secondary aortoduodenal fistula found 6 years after aortic reconstructive surgery, with the clinical presentation of upper gastrointestinal bleeding. On Immediate exploratory laparatomy, proximal part of abdominal Aorta was clamped. Duodonorrhaphy and aortic reconstruction with patch graft at the proximal suture line of aortic prosthesis was performed. Fortunately there was no pus, so tissue culture was not done. The intervention was concluded with an omentoplasty in order to protect the patch graft and to separate it from duodenorhaphy. Patient did well after the surgical management. Because of the increasing number of elective aortic aneurysm repairs in the aging population, it is likely that more patients with secondary aortoenteric fistula will present to the clinical physicians in the future. So, a high index of suspicion is necessary for prompt diagnosis and treatment of this actually life threatening event.

  5. Causes of secondary headache (image)

    Science.gov (United States)

    Temporomandibular joint, or TMJ, dysfunction, can be a cause of secondary headache. Secondary headaches result from underlying disorders which produce pain as a symptom. The TMJ may become painful and dysfunctional as a result of incorrect alignment ...

  6. Concepts of scale and scaling

    Science.gov (United States)

    Jianguo Wu; Harbin Li

    2006-01-01

    The relationship between pattern and process is of great interest in all natural and social sciences, and scale is an integral part of this relationship. It is now well documented that biophysical and socioeconomic patterns and processes operate on a wide range of spatial and temporal scales. In particular, the scale multiplicity and scale dependence of pattern,...

  7. Early Colleges at Scale: Impacts on Secondary and Postsecondary Outcomes

    Science.gov (United States)

    Lauen, Douglas L.; Fuller, Sarah; Barrett, Nathan; Janda, Ludmila

    2017-01-01

    We examine the impacts of early college high schools, small schools of choice located on college campuses. These schools provide a no-cost opportunity for students to earn college credit--or a 2-year degree--while in high school. Using rich administrative data on multiple cohorts of students and quasiexperimental methods informed by the…

  8. Secondary Vertex Finder Algorithm

    CERN Document Server

    Heer, Sebastian; The ATLAS collaboration

    2017-01-01

    If a jet originates from a b-quark, a b-hadron is formed during the fragmentation process. In its dominant decay modes, the b-hadron decays into a c-hadron via the electroweak interaction. Both b- and c-hadrons have lifetimes long enough, to travel a few millimetres before decaying. Thus displaced vertices from b- and subsequent c-hadron decays provide a strong signature for a b-jet. Reconstructing these secondary vertices (SV) and their properties is the aim of this algorithm. The performance of this algorithm is studied with tt̄ events, requiring at least one lepton, simulated at 13 TeV.

  9. Positive affect increases secondary control among causally uncertain individuals.

    Science.gov (United States)

    Tobin, Stephanie J; George, Melanie P

    2015-01-01

    Secondary control (acceptance of and adjustment to negative events) is thought to promote positive affect. We examined the opposite path: could positive affect increase secondary control, particularly among individuals high in causal uncertainty, who stand to benefit from it the most? In two studies, participants completed a causal uncertainty scale, thought about a problem while listening to affect-inducing music or no music, and then completed items that assessed secondary control. In Study 1, the music induced positive or negative affect. In Study 2, the music induced affect that was high or low in activation and positive or negative in valence. In both studies, we found that positive affect-inducing music increased secondary control among high causal uncertainty participants. Furthermore, trait affect did not account for the effects of causal uncertainty, and music did not influence primary control. These findings show that secondary control can fluctuate as a function of state affect.

  10. [Secondary orbital lymphoma].

    Science.gov (United States)

    Basanta, I; Sevillano, C; Álvarez, M D

    2015-09-01

    A case is presented of an 85 year-old Caucasian female with lymphoma that recurred in the orbit (secondary ocular adnexal lymphoma). The orbital tumour was a diffuse large B-cell lymphoma according to the REAL classification (Revised European-American Lymphoma Classification). Orbital lymphomas are predominantly B-cell proliferations of a variety of histological types, and most are low-grade tumours. Patients are usually middle-aged or elderly, and it is slightly more common in women. A palpable mass, proptosis and blepharoptosis are the most common signs of presentation. Copyright © 2011 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

  11. Transitions in Secondary Education

    DEFF Research Database (Denmark)

    Larsen, Britt Østergaard; Jensen, Leif; Pilegaard Jensen, Torben

    2014-01-01

    The purpose of this article is to investigate educational choices and attainment of children who experience social problems during their upbringing. The study explores the extent to which social problems can help explain the gaps in entry and dropout rates in upper secondary education in Denmark...... statistical model of educational progression. By using this method, we parcel educational attainment into a series of transitions and the model is able to control for educational selection and unobserved heterogeneity. We apply counterfactual analyses to allow a formal decomposition of the effects of social...... problems. The results show that social problems during upbringing have a large and significant effect on children's educational outcome and that the indicators of social problems explain about 20–30 per cent of the class differences in the students’ educational outcomes....

  12. Comparison Between the Original and Shortened Versions of the National Institutes of Health Stroke Scale in Ischemic Stroke Patients of Intermediate Severity.

    Science.gov (United States)

    Lee, Chun Fan; Venketasubramanian, Narayanaswamy; Wong, K S Lawrence; Chen, Christopher L H

    2016-01-01

    The 15-item National Institutes of Health Stroke Scale (NIHSS) has been critiqued for its complexity and variability, and shortened versions have been proposed. This study aimed to compare the measurement properties of the original version with 3 shortened versions with 11, 8, and 5 items, respectively. Analyses were performed using data from an international, double-blind randomized controlled trial investigating the efficacy of MLC601 on stroke recovery in patients with ischemic stroke of intermediate severity (Chinese Medicine Neuroaid Efficacy on Stroke recovery [CHIMES]). To compare discriminative ability and responsiveness to change, the effect sizes of the NIHSS scores in relation to modified Rankin Scale, mini-mental status examination, and Barthel index were estimated using regression analysis. For both discriminative ability and responsiveness to change, the original version exhibited a larger effect size (0.55 and 0.84) in relation to modified Rankin Scale than the other 3 shortened versions (0.35-0.46 and 0.74-0.78). The original 15-item NIHSS retained information that made it more discriminative and responsive to change than the shortened versions. We recommend future clinical researchers to use the full version NIHSS to evaluate patients' stroke severity. URL: http://www.clinicaltrials.gov. Unique identifier: NCT00554723. © 2015 American Heart Association, Inc.

  13. Unpacking the impoverished nature of secondary forests.

    Science.gov (United States)

    Parr, Catherine L; Bradshaw, Corey

    2012-09-01

    In a world where even documenting species declines in tropical systems is challenging enough, Klimes et al. raise the bar by addressing the deceptively simple, yet inherently complex, question of why species richness is lower in secondary forests. Using the first plot-scale inventory of arboreal ant nests, combined with an innovative rarefaction technique, they quantify the relative importance of a range of successional factors and highlight the contribution of beta diversity to the higher richness in primary forest. © 2012 The Author. Journal of Animal Ecology © 2012 British Ecological Society.

  14. Status of Secondary School Libraries under the Secondary ...

    African Journals Online (AJOL)

    This study was undertaken in Dodoma Municipal, Tanzania in order to assess the development and status of school library services under the Secondary Education Development Plan (SEDP). The study involved 44 secondary schools, 186 teachers, 44 heads of schools, 16 school librarians, one Regional Education Officer, ...

  15. Primary and secondary hypertriglyceridaemia.

    Science.gov (United States)

    Kolovou, Genovefa D; Anagnostopoulou, Katherine K; Kostakou, Peggy M; Bilianou, Helen; Mikhailidis, Dimitri P

    2009-04-01

    Familial hypertriglyceridaemia is inherited in an autosomal dominant manner. The responsible genetic abnormality is unknown but recently, a novel gene encoding apolipoprotein AV has been linked to familial hypertriglyceridaemia. All patients develop the same phenotype with elevated levels of very low density lipoproteins (VLDL) in plasma. The main disorder of this dyslipidaemia is decreased intestinal absorption of biliary acids, leading to a compensatory increase of VLDL production. In familial hypertriglyceridaemia, a marked increase in plasma triglyceride (TG) levels can cause acute pancreatitis. Moreover, patients with other genetic factors, like familial chylomicronaemia, familial combined hyperlipidaemia, familial dysbetalipoproteinaemia and other rare disorders (e.g. Tangier disease and fish eye disease) may present increase of TG levels or cholesterol levels or both. Secondary hypertriglyceridaemias include hypothyroidism, kidney abnormalities (e.g. nephrotic syndrome or chronic kidney failure), diabetes mellitus, heavy alcohol consumption and obesity. In men and postmenopausal women, it seems that estrogen deficiency is responsible for higher TG levels compared with premenopausal women postprandially. In every state -fasting or postprandial-, women demonstrate lower plasma TG levels compared with men. This fact is due not only to increased muscular TG uptake and storage but also to higher TG clearance. Many studies demonstrated an age impact on plasma TG increase and larger variation of fasting TG levels caused by age. Also, hypertriglyceridaemia (TG >150 mg/dl; 1.7 mmol/l) is one of the diagnostic criteria of metabolic syndrome. Finally, several drugs may increase TG levels (e.g. chlorthalidone or beta-blockers).

  16. Psychometric properties of the Academic Situations Specific Perceived Self-efficacy Scale in a Spanish students sample of Compulsory Secondary Education Propiedades psicométricas de la Escala de Autoeficacia Percibida Específica de Situaciones Académicas en una muestra de estudiantes españoles de Educación Secundaria Obligatoria

    Directory of Open Access Journals (Sweden)

    José M. García-Fernández

    2010-05-01

    Full Text Available The aim of this study was to analyse the psychometric properties of the Academic Situations Specific Perceived Self-efficacy Scale in a 656 Spanish sample of Compulsory Secondary Education students, aged 12 to 16. Factor analyses revealed that the SPSASS shows a unidimensional structure, with adequate indices of internal consistency (0.89 and test-retest reliability (0.87. Relationships between academic self-efficacy and academic goals, academic self-concept and academic performance supported the construct validity of the scale. Logistic regression models used to predict academic performance using self-efficacy as predictor, and the prediction of self-efficacy using performance as predictor provided empirical support for the self-regulatory functioning of self-efficacy. It was revealed that the probability of showing high self-efficacy increases in 94% for each point increase in grade point average, whereas the probability of academic success increases in 8% when perceived self-efficacy increases. El objetivo de este estudio consistió en analizar las propiedades psicométricas de la Escala de Autoeficacia Percibida Específica de Situaciones Académicas en una muestra de 656 estudiantes españoles de Educación Secundaria Obligatoria de 12 a 16 años. Los análisis factoriales revelaron que la EAPESA presenta una estructura unidimensional, con coeficientes de consistencia interna (0.89 y fiabilidad test-retest (0.87 adecuados. Las relaciones entre autoeficacia académica, metas académicas, autoconcepto académico y rendimiento escolar apoyaron la validez de constructo de la escala. Los modelos de regresión logística para la predicción del rendimiento académico a partir de la autoeficacia y la predicción de ésta a partir del rendimiento apoyaron empíricamente el papel autorregulatorio de la autoeficacia ya que la probabilidad de presentar alta autoeficacia aumenta un 94% por cada punto que aumenta la nota media, mientras que la

  17. Maslowian Scale.

    Science.gov (United States)

    Falk, C.; And Others

    The development of the Maslowian Scale, a method of revealing a picture of one's needs and concerns based on Abraham Maslow's levels of self-actualization, is described. This paper also explains how the scale is supported by the theories of L. Kohlberg, C. Rogers, and T. Rusk. After a literature search, a list of statements was generated…

  18. Helicity scalings

    Energy Technology Data Exchange (ETDEWEB)

    Plunian, F [ISTerre, CNRS, Universite Joseph Fourier, Grenoble (France); Lessinnes, T; Carati, D [Physique Statistique et Plasmas, Universite Libre de Bruxelles (Belgium); Stepanov, R, E-mail: Franck.Plunian@ujf-grenoble.fr [Institute of Continuous Media Mechanics of the Russian Academy of Science, Perm (Russian Federation)

    2011-12-22

    Using a helical shell model of turbulence, Chen et al. (2003) showed that both helicity and energy dissipate at the Kolmogorov scale, independently from any helicity input. This is in contradiction with a previous paper by Ditlevsen and Giuliani (2001) in which, using a GOY shell model of turbulence, they found that helicity dissipates at a scale larger than the Kolmogorov scale, and does depend on the helicity input. In a recent paper by Lessinnes et al. (2011), we showed that this discrepancy is due to the fact that in the GOY shell model only one helical mode (+ or -) is present at each scale instead of both modes in the helical shell model. Then, using the GOY model, the near cancellation of the helicity flux between the + and - modes cannot occur at small scales, as it should be in true turbulence. We review the main results with a focus on the numerical procedure needed to obtain accurate statistics.

  19. [Preventive dentistry 5. Secondary caries].

    NARCIS (Netherlands)

    Hollanders, A.C.C.; Kuper, N.K.; Opdam, N.J.M.; Huysmans, M.C.D.N.J.M.

    2017-01-01

    Secondary caries is reported as one of the most important reasons for replacing restorations. The patient's general caries risk plays an important role in the development of secondary caries. The connection, at the patient level, between various factors, the risk of caries and restoration factors,

  20. Cellular compartmentalization of secondary metabolism

    Directory of Open Access Journals (Sweden)

    H. Corby eKistler

    2015-02-01

    Full Text Available Fungal secondary metabolism is often considered apart from the essential housekeeping functions of the cell. However, there are clear links between fundamental cellular metabolism and the biochemical pathways leading to secondary metabolite synthesis. Besides utilizing key biochemical precursors shared with the most essential processes of the cell (e.g. amino acids, acetyl CoA, NADPH, enzymes for secondary metabolite synthesis are compartmentalized at conserved subcellular sites that position pathway enzymes to use these common biochemical precursors. Co-compartmentalization of secondary metabolism pathway enzymes also may function to channel precursors, promote pathway efficiency and sequester pathway intermediates and products from the rest of the cell. In this review we discuss the compartmentalization of three well-studied fungal secondary metabolite biosynthetic pathways for penicillin G, aflatoxin and deoxynivalenol, and summarize evidence used to infer subcellular localization. We also discuss how these metabolites potentially are trafficked within the cell and may be exported.

  1. Predictors of secondary traumatic stress among children's advocacy center forensic interviewers.

    Science.gov (United States)

    Bonach, Kathryn; Heckert, Alex

    2012-01-01

    This study examined various predictor variables that were hypothesized to impact secondary traumatic stress in forensic interviewers ( n = 257) from children's advocacy centers across the United States. Data were examined to investigate the relationship between organizational satisfaction, organizational buffers, and job support with secondary traumatic stress using the Secondary Traumatic Stress Scale. The most salient significant result was an inverse relationship between three indicators of job support and secondary traumatic stress. Also significant to secondary traumatic stress were the age of interviewer and whether the forensic interviewer had experienced at least one significant loss in the previous 12 months. Implications for future research, training, program practice, and policy are discussed.

  2. Framing scales and scaling frames

    NARCIS (Netherlands)

    Lieshout, van M.; Dewulf, A.; Aarts, M.N.C.; Termeer, C.J.A.M.

    2009-01-01

    Policy problems are not just out there. Actors highlight different aspects of a situation as problematic and situate the problem on different scales. In this study we will analyse the way actors apply scales in their talk (or texts) to frame the complex decision-making process of the establishment

  3. Secondary Students' Stable and Unstable Optics Conceptions Using Contextualized Questions

    Science.gov (United States)

    Chu, Hye-Eun; Treagust, David F.

    2014-01-01

    This study focuses on elucidating and explaining reasons for the stability of and interrelationships between students' conceptions about "Light Propagation" and "Visibility of Objects" using contextualized questions across 3 years of secondary schooling from Years 7 to 9. In a large-scale quantitative study involving 1,233…

  4. Assessment in Performance-Based Secondary Music Classes

    Science.gov (United States)

    Pellegrino, Kristen; Conway, Colleen M.; Russell, Joshua A.

    2015-01-01

    After sharing research findings about grading and assessment practices in secondary music ensemble classes, we offer examples of commonly used assessment tools (ratings scale, checklist, rubric) for the performance ensemble. Then, we explore the various purposes of assessment in performance-based music courses: (1) to meet state, national, and…

  5. Study Attitude and Academic Achievement at Secondary Level in Pakistan

    Science.gov (United States)

    Sarwar, Muhammad; Bashir, Muhamamd; Alam, Muhammad

    2010-01-01

    The author compared study attitudes of low and high achievers by using a self-developed study attitude scale (SAS) consisting of 36 items. Academic performance was measured through marks obtained by the students in the 9th grade examination conducted by the external body. The analysis revealed that the study attitude of secondary school students…

  6. A survey of perceived hindrances to junior secondary school ...

    African Journals Online (AJOL)

    This study investigated situations which Junior Secondary Schools (JSS) teachers perceived as hindrances to their teaching functions. A 30-item questionnaire with a 5-point scale was used to collect data from 116 science teachers who taught in private and public schools. The schools were based in rural and urban ...

  7. Numerical Modelling and Measurement in a Test Secondary Settling Tank

    DEFF Research Database (Denmark)

    Dahl, C.; Larsen, Torben; Petersen, O.

    1994-01-01

    and for comparing measured and calculated result. The numerical model could, fairly accuratly, predict the measured results and both the measured and the calculated results showed a flow field pattern identical to flow fields in full-scale secondary setling tanks. A specific calibration of the Bingham plastic...

  8. Hanford Site Secondary Waste Roadmap

    Energy Technology Data Exchange (ETDEWEB)

    Westsik, Joseph H.

    2009-01-29

    Summary The U.S. Department of Energy (DOE) is making plans to dispose of 54 million gallons of radioactive tank wastes at the Hanford Site near Richland, Washington. The high-level wastes and low-activity wastes will be vitrified and placed in permanent disposal sites. Processing of the tank wastes will generate secondary wastes, including routine solid wastes and liquid process effluents, and these need to be processed and disposed of also. The Department of Energy Office of Waste Processing sponsored a meeting to develop a roadmap to outline the steps necessary to design the secondary waste forms. Representatives from DOE, the U.S. Environmental Protection Agency, the Washington State Department of Ecology, the Oregon Department of Energy, Nuclear Regulatory Commission, technical experts from the DOE national laboratories, academia, and private consultants convened in Richland, Washington, during the week of July 21-23, 2008, to participate in a workshop to identify the risks and uncertainties associated with the treatment and disposal of the secondary wastes and to develop a roadmap for addressing those risks and uncertainties. This report describes the results of the roadmap meeting in Richland. Processing of the tank wastes will generate secondary wastes, including routine solid wastes and liquid process effluents. The secondary waste roadmap workshop focused on the waste streams that contained the largest fractions of the 129I and 99Tc that the Integrated Disposal Facility risk assessment analyses were showing to have the largest contribution to the estimated IDF disposal impacts to groundwater. Thus, the roadmapping effort was to focus on the scrubber/off-gas treatment liquids with 99Tc to be sent to the Effluent Treatment Facility for treatment and solidification and the silver mordenite and carbon beds with the captured 129I to be packaged and sent to the IDF. At the highest level, the secondary waste roadmap includes elements addressing regulatory and

  9. Conserved secondary structures in Aspergillus.

    Directory of Open Access Journals (Sweden)

    Abigail Manson McGuire

    2008-07-01

    Full Text Available Recent evidence suggests that the number and variety of functional RNAs (ncRNAs as well as cis-acting RNA elements within mRNAs is much higher than previously thought; thus, the ability to computationally predict and analyze RNAs has taken on new importance. We have computationally studied the secondary structures in an alignment of six Aspergillus genomes. Little is known about the RNAs present in this set of fungi, and this diverse set of genomes has an optimal level of sequence conservation for observing the correlated evolution of base-pairs seen in RNAs.We report the results of a whole-genome search for evolutionarily conserved secondary structures, as well as the results of clustering these predicted secondary structures by structural similarity. We find a total of 7450 predicted secondary structures, including a new predicted approximately 60 bp long hairpin motif found primarily inside introns. We find no evidence for microRNAs. Different types of genomic regions are over-represented in different classes of predicted secondary structures. Exons contain the longest motifs (primarily long, branched hairpins, 5' UTRs primarily contain groupings of short hairpins located near the start codon, and 3' UTRs contain very little secondary structure compared to other regions. There is a large concentration of short hairpins just inside the boundaries of exons. The density of predicted intronic RNAs increases with the length of introns, and the density of predicted secondary structures within mRNA coding regions increases with the number of introns in a gene.There are many conserved, high-confidence RNAs of unknown function in these Aspergillus genomes, as well as interesting spatial distributions of predicted secondary structures. This study increases our knowledge of secondary structure in these aspergillus organisms.

  10. Secondary maxima in ozone profiles

    Directory of Open Access Journals (Sweden)

    R. Lemoine

    2004-01-01

    Full Text Available Ozone profiles from balloon soundings as well as SAGEII ozone profiles were used to detect anomalous large ozone concentrations of ozone in the lower stratosphere. These secondary ozone maxima are found to be the result of differential advection of ozone-poor and ozone-rich air associated with Rossby wave breaking events. The frequency and intensity of secondary ozone maxima and their geographical distribution is presented. The occurrence and amplitude of ozone secondary maxima is connected to ozone variability and trend at Uccle and account for a large part of the total ozone and lower stratospheric ozone variability.

  11. Targets and Secondary Beam Extraction

    Science.gov (United States)

    Noah, Etam

    2014-02-01

    Several applications make use of secondary beams of particles generated by the interaction of a primary beam of particles with a target. Spallation neutrons, bremsstrahlung photon-produced neutrons, radioactive ions and neutrinos are available to users at state-of-the-art facilities worldwide. Plans for even higher secondary beam intensities place severe constraints on the design of targets. This article reports on the main targetry challenges and highlights a variety of solutions for targetry and secondary beam extraction. Issues related to target station layout, instrumentation at the beam-target interface, safety and radioprotection are also discussed.

  12. Scaling down

    Directory of Open Access Journals (Sweden)

    Ronald L Breiger

    2015-11-01

    Full Text Available While “scaling up” is a lively topic in network science and Big Data analysis today, my purpose in this essay is to articulate an alternative problem, that of “scaling down,” which I believe will also require increased attention in coming years. “Scaling down” is the problem of how macro-level features of Big Data affect, shape, and evoke lower-level features and processes. I identify four aspects of this problem: the extent to which findings from studies of Facebook and other Big-Data platforms apply to human behavior at the scale of church suppers and department politics where we spend much of our lives; the extent to which the mathematics of scaling might be consistent with behavioral principles, moving beyond a “universal” theory of networks to the study of variation within and between networks; and how a large social field, including its history and culture, shapes the typical representations, interactions, and strategies at local levels in a text or social network.

  13. Secondary Sclerosing Cholangitis During Pregnancy

    National Research Council Canada - National Science Library

    Abdulqader, Yasir; Chuang, Keng-Yu; Ravi, Jyotsna; Nadir, Abdul

    2016-01-01

    ... of secondary sclerosing cholangitis. Maternal and fetal outcomes of primary sclerosis cholangitis have been reported, and this case highlights the importance of considering other diseases besides the benign intrahepatic cholestasis...

  14. Secondary Sclerosing Cholangitis During Pregnancy

    OpenAIRE

    Abdulqader, Yasir; Chuang, Keng-Yu; Ravi, Jyotsna; Nadir, Abdul

    2016-01-01

    We report a case of secondary sclerosing cholangitis that manifested itself during pregnancy. A tentative diagnosis of intrahepatic cholestasis of pregnancy was considered, but after her third delivery, a liver biopsy and imaging, as well as review of past records, confirmed the diagnosis of secondary sclerosing cholangitis. Maternal and fetal outcomes of primary sclerosis cholangitis have been reported, and this case highlights the importance of considering other diseases besides the benign ...

  15. Secondary Sclerosing Cholangitis During Pregnancy.

    Science.gov (United States)

    Abdulqader, Yasir; Chuang, Keng-Yu; Ravi, Jyotsna; Nadir, Abdul

    2016-07-01

    We report a case of secondary sclerosing cholangitis that manifested itself during pregnancy. A tentative diagnosis of intrahepatic cholestasis of pregnancy was considered, but after her third delivery, a liver biopsy and imaging, as well as review of past records, confirmed the diagnosis of secondary sclerosing cholangitis. Maternal and fetal outcomes of primary sclerosis cholangitis have been reported, and this case highlights the importance of considering other diseases besides the benign intrahepatic cholestasis of pregnancy as a cause of cholestasis in pregnancy.

  16. Secondary liquefaction in ethanol production

    DEFF Research Database (Denmark)

    2007-01-01

    The invention relates to a method of producing ethanol by fermentation, said method comprising a secondary liquefaction step in the presence of a themostable acid alpha-amylase or, a themostable maltogenic acid alpha-amylase.......The invention relates to a method of producing ethanol by fermentation, said method comprising a secondary liquefaction step in the presence of a themostable acid alpha-amylase or, a themostable maltogenic acid alpha-amylase....

  17. Secondary databases in equine research

    OpenAIRE

    Penell, Johanna

    2009-01-01

    Knowledge on disease occurrence in the Swedish equine population is lacking. Secondary data (data not produced primarily for research) including medical information offer potential to investigate disease occurrence in populations without primary data collection. This thesis explored the potential use of two nation-wide secondary equine databases for research on diseases in the Swedish horse population. The data quality in one insurance database and one database from a national equine clinic n...

  18. Scaling Rules!

    Science.gov (United States)

    Malkinson, Dan; Wittenberg, Lea

    2015-04-01

    Scaling is a fundamental issue in any spatially or temporally hierarchical system. Defining domains and identifying the boundaries of the hierarchical levels may be a challenging task. Hierarchical systems may be broadly classified to two categories: compartmental and continuous ones. Examples of compartmental systems include: governments, companies, computerized networks, biological taxonomy and others. In such systems the compartments, and hence the various levels and their constituents are easily delineated. In contrast, in continuous systems, such as geomorphological, ecological or climatological ones, detecting the boundaries of the various levels may be difficult. We propose that in continuous hierarchical systems a transition from one functional scale to another is associated with increased system variance. Crossing from a domain of one scale to the domain of another is associated with a transition or substitution of the dominant drivers operating in the system. Accordingly we suggest that crossing this boundary is characterized by increased variance, or a "variance leap", which stabilizes, until crossing to the next domain or hierarchy level. To assess this we compiled sediment yield data from studies conducted at various spatial scales and from different environments. The studies were partitioned to ones conducted in undisturbed environments, and those conducted in disturbed environments, specifically by wildfires. The studies were conducted in plots as small as 1 m2, and watersheds larger than 555000 ha. Regressing sediment yield against plot size, and incrementally calculating the variance in the systems, enabled us to detect domains where variance values were exceedingly high. We propose that at these domains scale-crossing occurs, and the systems transition from one hierarchical level to another. Moreover, the degree of the "variance leaps" characterizes the degree of connectivity among the scales.

  19. The Interaction Effects of Gender and Grade Level on Secondary School Students' Attitude towards Learning Chemistry

    Science.gov (United States)

    Heng, Chua Kah; Karpudewan, Mageswary

    2015-01-01

    This quantitative study reports the effects of gender and grade level on secondary students' attitude towards chemistry lessons. For this purpose, the Attitude towards Chemistry Lessons Scale (ATCLS) was administered to 446 secondary school students between 16-19 years old. The ATCLS consists of four different subscales: liking for chemistry…

  20. "I Am the Hate that Dare Not Speak Its Name": Dealing with Homophobia in Secondary Schools

    Science.gov (United States)

    Adams, Natasha; Cox, Tamsin; Dunstan, Laura

    2004-01-01

    This paper describes the outcomes of a small-scale project involving 19 secondary schools. The project investigated how effectively issues of homophobic bullying and sexualities were addressed through secondary schools' formal policies and areas of the curriculum. Outcomes indicate that sexual orientation was mentioned in two-thirds of Equal…

  1. Leadership styles in secondary school science teachers

    Science.gov (United States)

    Lawson, Michael A.

    A comparison of United States secondary school science teachers who mentor high quality student research and teachers who do not mentor research was conducted using a demographic survey and the Multifactor Leadership Questionnaire-Form 5X. The major demographic difference between the two groups was a significantly greater number of years of teaching experience in the research group, a factor that correlated significantly with Extra Effort in students. Research group teachers self-reported higher mean scores than non-research group teachers on the five transformational leadership scales plus the transactional scale of Contingent Reward; however, a Multivariate Analysis of Variance found no significant difference between the groups. Independent t-tests found no significant difference between the groups based upon the remaining transactional scales. The research group was found to be significantly higher on the outcome variable of Extra Effort generated by students while the non-research group rated themselves significantly higher on Satisfaction of students. Transformational leadership in teachers should be addressed by future studies as a possible method of identifying motivational teachers.

  2. The Americleft Project: Burden of Care from Secondary Surgery

    Science.gov (United States)

    Mara, Constance A.; Long, Ross E.; Daskalogiannakis, John; Russell, Kathleen A.; Mercado, Ana M.; Hathaway, Ronald R.; Carle, Adam C.; Semb, Gunvor; Shaw, William C.

    2015-01-01

    Background: The burden of care for children with cleft lip and palate extends beyond primary repair. Children may undergo multiple secondary surgeries to improve appearance or speech. The purpose of this study was to compare the use of secondary surgery between cleft centers. Methods: This retrospective cohort study included 130 children with complete unilateral cleft lip and palate treated consecutively at 4 cleft centers in North America. Data were collected on all lip, palate, and nasal surgeries. Nasolabial appearance was rated by a panel of judges using the Asher-McDade scale. Risk of secondary surgery was compared between centers using the log-rank test, and hazard ratios estimated with a Cox proportional hazards model. Results: Median follow-up was 18 years (interquartile range, 15–19). There were significant differences among centers in the risks of secondary lip surgery (P 0.10). Conclusions: Although some cleft centers were significantly more likely to perform secondary surgery, the use of secondary surgery did not achieve significantly better nasolabial appearance than what was achieved by children who underwent only primary surgery. PMID:26301131

  3. Microalgal Cultivation in Secondary Effluent: Recent Developments and Future Work

    Directory of Open Access Journals (Sweden)

    Junping Lv

    2017-01-01

    Full Text Available Eutrophication of water catchments and the greenhouse effect are major challenges in developing the global economy in the near future. Secondary effluents, containing high amounts of nitrogen and phosphorus, need further treatment before being discharged into receiving water bodies. At the same time, new environmentally friendly energy sources need to be developed. Integrating microalgal cultivation for the production of biodiesel feedstock with the treatment of secondary effluent is one way of addressing both issues. This article provides a comprehensive review of the latest progress in microalgal cultivation in secondary effluent to remove pollutants and accumulate lipids. Researchers have discovered that microalgae remove nitrogen and phosphorus effectively from secondary effluent, accumulating biomass and lipids in the process. Immobilization of appropriate microalgae, and establishing a consortium of microalgae and/or bacteria, were both found to be feasible ways to enhance pollutant removal and lipid production. Demonstrations of pilot-scale microalgal cultures in secondary effluent have also taken place. However there is still much work to be done in improving pollutants removal, biomass production, and lipid accumulation in secondary effluent. This includes screening microalgae, constructing the consortium, making use of flue gas and nitrogen, developing technologies related to microalgal harvesting, and using lipid-extracted algal residues (LEA.

  4. Nuclear scales

    Energy Technology Data Exchange (ETDEWEB)

    Friar, J.L.

    1998-12-01

    Nuclear scales are discussed from the nuclear physics viewpoint. The conventional nuclear potential is characterized as a black box that interpolates nucleon-nucleon (NN) data, while being constrained by the best possible theoretical input. The latter consists of the longer-range parts of the NN force (e.g., OPEP, TPEP, the {pi}-{gamma} force), which can be calculated using chiral perturbation theory and gauged using modern phase-shift analyses. The shorter-range parts of the force are effectively parameterized by moments of the interaction that are independent of the details of the force model, in analogy to chiral perturbation theory. Results of GFMC calculations in light nuclei are interpreted in terms of fundamental scales, which are in good agreement with expectations from chiral effective field theories. Problems with spin-orbit-type observables are noted.

  5. Demarcation of secondary hyperalgesia zones

    DEFF Research Database (Denmark)

    Ringsted, Thomas K; Enghuus, Casper; Petersen, Morten A

    2015-01-01

    BACKGROUND: Secondary hyperalgesia is increased sensitivity in normal tissue near an injury, and it is a measure of central sensitization reflecting injury-related effects on the CNS. Secondary hyperalgesia areas (SHAs), usually assessed by polyamide monofilaments, are important outcomes in studies...... of analgesic drug effects in humans. However, since the methods applied in demarcating the secondary hyperalgesia zone seem inconsistent across studies, we examined the effect of a standardized approach upon the measurement of SHA following a first degree burn injury (BI). NEW METHOD: The study was a two......-observer, test-retest study with the two sessions separated by 6wk. An observer-blinded design adjusted to examine day-to-day and observer-to-observer variability in SHA was used. In 23 healthy volunteers (12 females/11 males) a BI was induced by a contact thermode (47.0°C, 420s, 2.5×5.0cm(2)). The SHA...

  6. An Inclusive Secondary School in Bratislava

    Directory of Open Access Journals (Sweden)

    Gajdošová Eva

    2016-12-01

    Full Text Available The study presents a characterization of an inclusive secondary school in Bratislava and provides information about the forms and methods used in the work of the teachers, school psychologists, special teachers with regard to students with special needs (students with Attention and Hyperactivity Disorder, i.e. ADHD, with learning difficulties, with emotional and behaviour difficulties, etc., who are educated together with mainstream students. It also provides information on the first results of the measurements of the socio-emotional health of the students in the inclusive school, both as to its overall level (covitality index and as to the level of the four psychological dimensions of mental health. The pilot project of the inclusive school confirms that inclusive secondary schools and inclusive education operating within the intentions of positive psychology help the students to develop their cognitive and socio-emotional competences, to create favourable attitudes to diversity, to form the students’ scale of positive values and to encourage positive interpersonal relationships, social cohesion and social classroom climate.

  7. Secondary Education in Greece. Guide to Secondary Education in Europe.

    Science.gov (United States)

    Kallen, Denis

    Cultural and national history have profoundly modeled Greek society and continue to play a vital role in Greek policy and in cultural and social life. This handbook provides a brief overview of secondary education in Greece. The first part describes the country's societal, historical, and political background; educational history and current…

  8. Secondary debris effects on personnel

    NARCIS (Netherlands)

    Dorsch, H.; Sohn, H.; Boonacker, B.; Duvall, P.

    2015-01-01

    Effects of munitions during operations in urban terrain are critical not only for enemy and allied soldiers but also to civilians. Besides the primary weapon effects caused by penetrating fragments, and blast overpressure; secondary effects from wall debris may contribute to the damage process. To

  9. Teacher Absenteeism in Secondary Education.

    Science.gov (United States)

    Scott, K. Dow; Wimbush, James C.

    1991-01-01

    Uses an existing model of attendance behavior to examine attitudinal, demographic, and absenteeism data from 265 secondary school teachers. Canonical correlation analysis revealed that teacher absenteeism was significantly related to distance to work, gender, job involvement, and job satisfaction. (58 references) (MLH)

  10. Portugal's Secondary School Modernisation Programme

    Science.gov (United States)

    Heitor, Teresa V.; Freire da Silva, Jose M. R.

    2009-01-01

    The aim of the Secondary School Modernisation Programme, being implemented in Portugal by "Parque Escolar, EPE", is based on the pursuit of quality and makes Portuguese education a potential international benchmark. This paper discusses the strategies adopted to reorganise school spaces. It describes the conceptual model and highlights…

  11. Population Genomics of Secondary Contact

    Directory of Open Access Journals (Sweden)

    Anthony Geneva

    2010-06-01

    Full Text Available One common form of reticulate evolution arises as a consequence of secondary contact between previously allopatric populations. Using extensive coalescent simulations, we describe the conditions for, and extent of, the introgression of genetic material into the genome of a colonizing population from an endemic population. The simulated coalescent histories are sampled from models that describe the evolution of entire chromosomes, thereby allowing the expected length of introgressed haplotypes to be estimated. The results indicate that our ability to identify reticulate evolution from genetic data is highly variable and depends critically upon the duration of the period of allopatry, the timing of the secondary contact event, as well as the sizes of the populations at the time of contact. One particularly interesting result arises when secondary contact occurs close to the time of a severe founder event, in this case, genetic introgression can be substantially more difficult to detect. However, if secondary contact occurs after such a founding event, when the range of the colonizing population increases, introgression is more readily detectable across the genome. This result may have important implications for our ability to detect introgression between ancestrally bottlenecked modern human populations and archaic hominin species, such as Neanderthals.

  12. Gender imbalance in secondary schools

    Directory of Open Access Journals (Sweden)

    Catherine Howgego Mugisha

    2005-01-01

    Full Text Available Significantly fewer girls than boys attend schools inrefugee camps. As the level of education increases, there is a corresponding decrease in the numbers of female participants. This has resulted in a severe gender imbalance in refugee secondary schools.

  13. General Secondary or Vocational Education

    Science.gov (United States)

    Popova, S.A.

    2016-01-01

    After the completion of the basic general education program (after the ninth grade), Russian students must choose one of two educational trajectories: to continue their general secondary education (enroll in 10th grade) or to enter a vocational education program. What do Russian schoolchildren choose? This article examines data from the last 15…

  14. Secondary Health Occupations Education Curriculum.

    Science.gov (United States)

    Matzen, Shelley; Muhl, V. Jane

    This color coded curriculum guide for secondary health occupations in Iowa provides units for the first phase of the curriculum, career exploration of the health occupations. The nine units cover the following topics: (1) introduction to health occupations; (2) health occupations career exploration; (3) communication skills; (4) self-care and…

  15. Summarizing primary and secondary effects

    DEFF Research Database (Denmark)

    Karlson, Kristian Bernt

    2013-01-01

    Current methods for decomposing class differentials in educational decisions into primary and secondary effects produce many parameters, rendering them ill-equipped for parsimonious comparisons across countries or birth cohorts. This paper develops a parametric method that provides an optimal sum...

  16. Heat pain detection threshold is associated with the area of secondary hyperalgesia following brief thermal sensitization

    DEFF Research Database (Denmark)

    Hansen, Morten Sejer; Wetterslev, Jørn; Pipper, Christian Bressen

    2017-01-01

    participants was included and tested on 2 separate study days with BTS (45°C, 3 minutes), HPDT, and pain during thermal stimulation (45°C, 1 minute). Areas of secondary hyperalgesia were quantified after monofilament pinprick stimulation. The pain catastrophizing scale (PCS) and hospital anxiety and depression......INTRODUCTION: The area of secondary hyperalgesia following brief thermal sensitization (BTS) of the skin and heat pain detection thresholds (HPDT) may both have predictive abilities in regards to pain sensitivity and clinical pain states. The association between HPDT and secondary hyperalgesia...... scale (HADS) were also applied. RESULTS: A significant association between HPDT and the size of the area of secondary hyperalgesia (parea of secondary hyperalgesia due to a 1-degree increase in HPDT was estimated to be -27.38 cm(2), 95% confidence interval (CI...

  17. Development and Psychometric Evaluation of the School Bullying Scales: A Rasch Measurement Approach

    Science.gov (United States)

    Cheng, Ying-Yao; Chen, Li-Ming; Liu, Kun-Shia; Chen, Yi-Ling

    2011-01-01

    The study aims to develop three school bullying scales--the Bully Scale, the Victim Scale, and the Witness Scale--to assess secondary school students' bullying behaviors, including physical bullying, verbal bullying, relational bullying, and cyber bullying. The items of the three scales were developed from viewpoints of bullies, victims, and…

  18. On the spectrum of stable secondary nuclei in cosmic rays

    Science.gov (United States)

    Blasi, P.

    2017-10-01

    The ratio of the fluxes of secondary and primary nuclei in cosmic rays has long been used as an indicator of the grammage traversed in the journey of cosmic ray particles throughout the Galaxy. The basic idea is that primary particles are accelerated in astrophysical sources, such as supernova remnant shocks and eventually propagate in the Galactic volume, occasionally interacting with gas, mainly in the disc of the Galaxy, and there they produce secondary nuclei through spallation. At sufficiently high energy, typically ≳100 GeV/n, the ratio of fluxes of the secondary nucleus to that of the main primary nucleus is found to scale as Ek^{-δ }, where Ek is the energy per nucleon (a conserved quantity in spallation reactions) and δ identifies the energy dependence of the diffusion coefficient. The same shock waves that may be responsible for cosmic ray acceleration in the first place also pick up any other charged particle in the upstream, provided being above threshold for injection. The secondary nuclei produced by spallation in the interstellar medium are no exception, hence they also get accelerated. This effect is unavoidable, only its strength may be subject of debate. We compute the spectrum of secondary elements such as boron and lithium taking into account shock reacceleration and compare our predictions with the recent observations of the B/C ratio and preliminary measurements of the boron and lithium flux. Both these sets of data seem to confirm that reacceleration of secondary nuclei indeed plays an important role, thereby affecting the validity of those scaling rules that are often used in cosmic ray physics.

  19. Current profile of secondary glaucomas

    Directory of Open Access Journals (Sweden)

    Gadia Ritu

    2008-01-01

    Full Text Available Purpose: To study the current profile of secondary glaucomas for their incidence and to identify risk factors. Materials and Methods: In this retrospective chart review, 2997 patients newly diagnosed and referred with glaucoma to our tertiary glaucoma center in the year 2005 were included. Evaluation of all cases was done on the basis of a detailed history and recorded examination including vision, intraocular pressure (IOP, anterior segment examination, gonioscopy and fundus evaluation by glaucoma specialists. Demographic data, etiology of secondary glaucoma, and any other significant findings were noted. Results: Of 2997 referred patients, 2650 had glaucoma or were glaucoma suspects. Of all glaucoma patients or glaucoma suspects, 579 patients (21.84% had secondary glaucoma. Age distribution was as follows: 25% were between 0-20 years; 27% were between 21-40 years; 30% were between 41-60 years and 18% were> 60 years. The male female ratio was 2.2. Frequent causes of secondary glaucoma were post - vitrectomy 14%, trauma 13%, corneo-iridic scar 12%, aphakia 11%, neovascular glaucoma 9%. Post-vitrectomy glaucoma eyes had vitreous substitutes in 83% cases of which 66% eyes had retained silicone oil for more than three months. Vision ≤20/200 was present in 63% eyes, 57% eyes had baseline IOP > 30 mm Hg. Of all traumatic glaucoma patients, 71% cases were < 30 years of age. Fifty per cent had baseline IOP of> 30 mm Hg and vision ≤20/200. Conclusions: Most patients with secondary glaucoma have poor vision (≤20/200 with high IOP and advanced fundus changes at presentation.

  20. SECONDARY OSTEOARTHRITIS IN RHEUMATOID ARTHRITIS

    Directory of Open Access Journals (Sweden)

    I. A. Starodubtseva

    2015-01-01

    Full Text Available The paper considers the problems of comorbidities in patients with rheumatoid arthritis (RA. Two or more RA-related conditions were diagnosed according to the results of the QUEST-RA program implemented in 34 countries. Osteoarthritis along with hypertension, hyperlipidemia, and osteoporosis was detected among the most commonly diseases. Owing to expanded diagnostic capabilities, the recognition and treatment of the comorbidities have recently received much attention, as embodied in the draft Association of Rheumatologists of Russia Guidelines for RA management (2014; Part 1. The concept and major characteristics of secondary osteoarthritis in RA are analyzed. It is precisely the inflammatory process and underlying disease-related risk factors, including treatment, that have impact on the development of secondary osteoarthritis and patients’ quality of life as a whole. All this allows an inference about the mechanisms closely intertwined with the underlying disease for the development of secondary osteoarthritis, which initiates cartilage damage and further remodeling. Primary and secondary osteoarthritis was comparatively analyzed. Particular emphasis is placed on current cartilage biomarkers, their diagnostic value and role in monitoring the efficiency of treatment in clinical trials. The paper provides a comparative analysis of detectable serum and urine biomarkers according to the results of the complex analysis made by the National Institutes of Health. Particular attention is given to cartilage oligomeric matrix protein (COMP. Foreign authors’ investigations suggest that there is a relationship between serum COMP levels and disease severity and joint X-ray changes. There is evidence for the efficacy of hyaluronic acid used in the treatment of secondary osteoarthritis in patients with RA. 

  1. Validation of the Hindi version of National Institute of Health Stroke Scale.

    Science.gov (United States)

    Prasad, Kameshwar; Dash, Deepa; Kumar, Amit

    2012-01-01

    To determine the reliability and validity of the National Institute of Health Stroke Scale (NIHSS) with the Hindi and Indian adaptation of items 9 and 10. NIHSS items 9 and 10 were modified and culturally adapted at All India Institute of Medical Sciences (AIIMS) and the resulting version was termed as Hindi version (HV-NIHSS). HV-NIHSS was applied by two independent investigators on 107 patients with stroke. Inter-observer agreement and intra-class correlation coefficients were calculated. The predictive validity of the HV-NIHSS was calculated using functional outcome after three months in the form of modified Rankin Scale (mRS) and Barthel Index (BI). The study included 107 patients of stroke recruited from a tertiary referral hospital at Delhi between November 1, 2009, and October 1, 2010; the mean age of these patients was 56.26±13.84 years and 65.4% of them had suffered ischemic stroke. Inter-rater reliability was high between the two examiners, with Pearson's r ranging from 0.72 to 0.99 for the 15 items on the Scale. Intra-class correlation coefficient for the total score was 0.995 (95% CI-0.993-0.997). Concurrent construct validity was established between HV-NIHSS and baseline Glasgow Coma Scale, with a high correlation (Spearman coefficient = -0.863, PHindi language version of the NIHSS developed at AIIMS appears reliable and valid when applied to a Hindi-speaking population.

  2. Validation Study of the Abbreviated Math Anxiety Scale: Spanish Adaptation

    Science.gov (United States)

    Brown, Jennifer L.; Sifuentes, Lucía Macías

    2016-01-01

    With growing numbers of Hispanic students enrolling in post-secondary school, there is a need to increase retention and graduation rates. The purpose of this study was to validate the Spanish adaptation of the Abbreviated Math Anxiety Scale (AMAS). The AMAS was translated and administered to 804 freshman students at a post-secondary institution in…

  3. Clinician judgment vs formal scales for predicting intracerebral hemorrhage outcomes

    Science.gov (United States)

    Dell, Cameron A.; Sparks, Mary J.; Watson, Tiffany D.; Langefeld, Carl D.; Comeau, Mary E.; Rosand, Jonathan; Battey, Thomas W.K.; Koch, Sebastian; Perez, Mario L.; James, Michael L.; McFarlin, Jessica; Osborne, Jennifer L.; Woo, Daniel; Kittner, Steven J.; Sheth, Kevin N.

    2016-01-01

    Objective: To compare the performance of formal prognostic instruments vs subjective clinical judgment with regards to predicting functional outcome in patients with spontaneous intracerebral hemorrhage (ICH). Methods: This prospective observational study enrolled 121 ICH patients hospitalized at 5 US tertiary care centers. Within 24 hours of each patient's admission to the hospital, one physician and one nurse on each patient's clinical team were each asked to predict the patient's modified Rankin Scale (mRS) score at 3 months and to indicate whether he or she would recommend comfort measures. The admission ICH score and FUNC score, 2 prognostic scales selected for their common use in neurologic practice, were calculated for each patient. Spearman rank correlation coefficients (r) with respect to patients' actual 3-month mRS for the physician and nursing predictions were compared against the same correlation coefficients for the ICH score and FUNC score. Results: The absolute value of the correlation coefficient for physician predictions with respect to actual outcome (0.75) was higher than that of either the ICH score (0.62, p = 0.057) or the FUNC score (0.56, p = 0.01). The nursing predictions of outcome (r = 0.72) also trended towards an accuracy advantage over the ICH score (p = 0.09) and FUNC score (p = 0.03). In an analysis that excluded patients for whom comfort care was recommended, the 65 available attending physician predictions retained greater accuracy (r = 0.73) than either the ICH score (r = 0.50, p = 0.02) or the FUNC score (r = 0.42, p = 0.004). Conclusions: Early subjective clinical judgment of physicians correlates more closely with 3-month outcome after ICH than prognostic scales. PMID:26674335

  4. Development of fungal cell factories for the production of secondary metabolites: Linking genomics and metabolism

    Directory of Open Access Journals (Sweden)

    Jens Christian Nielsen

    2017-03-01

    Full Text Available The genomic era has revolutionized research on secondary metabolites and bioinformatics methods have in recent years revived the antibiotic discovery process after decades with only few new active molecules being identified. New computational tools are driven by genomics and metabolomics analysis, and enables rapid identification of novel secondary metabolites. To translate this increased discovery rate into industrial exploitation, it is necessary to integrate secondary metabolite pathways in the metabolic engineering process. In this review, we will describe the novel advances in discovery of secondary metabolites produced by filamentous fungi, highlight the utilization of genome-scale metabolic models (GEMs in the design of fungal cell factories for the production of secondary metabolites and review strategies for optimizing secondary metabolite production through the construction of high yielding platform cell factories.

  5. Development of fungal cell factories for the production of secondary metabolites: Linking genomics and metabolism.

    Science.gov (United States)

    Nielsen, Jens Christian; Nielsen, Jens

    2017-03-01

    The genomic era has revolutionized research on secondary metabolites and bioinformatics methods have in recent years revived the antibiotic discovery process after decades with only few new active molecules being identified. New computational tools are driven by genomics and metabolomics analysis, and enables rapid identification of novel secondary metabolites. To translate this increased discovery rate into industrial exploitation, it is necessary to integrate secondary metabolite pathways in the metabolic engineering process. In this review, we will describe the novel advances in discovery of secondary metabolites produced by filamentous fungi, highlight the utilization of genome-scale metabolic models (GEMs) in the design of fungal cell factories for the production of secondary metabolites and review strategies for optimizing secondary metabolite production through the construction of high yielding platform cell factories.

  6. "APEC Blue": Secondary Aerosol Reductions from Emission Controls in Beijing.

    Science.gov (United States)

    Sun, Yele; Wang, Zifa; Wild, Oliver; Xu, Weiqi; Chen, Chen; Fu, Pingqing; Du, Wei; Zhou, Libo; Zhang, Qi; Han, Tingting; Wang, Qingqing; Pan, Xiaole; Zheng, Haitao; Li, Jie; Guo, Xiaofeng; Liu, Jianguo; Worsnop, Douglas R

    2016-02-18

    China implemented strict emission control measures in Beijing and surrounding regions to ensure good air quality during the 2014 Asia-Pacific Economic Cooperation (APEC) summit. We conducted synchronous aerosol particle measurements with two aerosol mass spectrometers at different heights on a meteorological tower in urban Beijing to investigate the variations in particulate composition, sources and size distributions in response to emission controls. Our results show consistently large reductions in secondary inorganic aerosol (SIA) of 61-67% and 51-57%, and in secondary organic aerosol (SOA) of 55% and 37%, at 260 m and ground level, respectively, during the APEC summit. These changes were mainly caused by large reductions in accumulation mode particles and by suppression of the growth of SIA and SOA by a factor of 2-3, which led to blue sky days during APEC commonly referred to as "APEC Blue". We propose a conceptual framework for the evolution of primary and secondary species and highlight the importance of regional atmospheric transport in the formation of severe pollution episodes in Beijing. Our results indicate that reducing the precursors of secondary aerosol over regional scales is crucial and effective in suppressing the formation of secondary particulates and mitigating PM pollution.

  7. Visiting Auschwitz: Evidence of Secondary Traumatization Among High School Students.

    Science.gov (United States)

    Bilewicz, Michał; Wojcik, Adrian Dominik

    2017-11-27

    Secondary traumatic stress has been intensively studied among survivors' therapists, family members, and trauma researchers. We claim that people who are exposed to reminders of past traumatic experiences when visiting places of memory or museum exhibitions could also develop secondary trauma symptoms. Thus, scholars and practitioners must better understand how such places related to historical traumatization (e.g., Holocaust memorial sites) can affect the psychological well-being of visitors. The main aim of this quantitative longitudinal study was to assess the scale of secondary traumatization among visitors to such places. The study found that the syndrome of secondary traumatic stress was observed among 13.2% of high school visitors to the Auschwitz memorial museum. Longitudinal analysis revealed that empathic reactions to the visit in Auschwitz (e.g., a greater inclusion of victims into the self) were associated with higher levels of secondary traumatic stress levels 1 month after the visit. This study suggests that visits to places related to traumatic past events should be preceded by a more intense elaboration of Holocaust history and by proper psychological preparations. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  8. Low-power heat pump systems combining two organic Rankine cycles; Applications de pompe a chaleur. A l'exemple des systemes ORC-ORC de petite puissance

    Energy Technology Data Exchange (ETDEWEB)

    Demierre, J.

    2009-07-01

    In this basic article that includes many diagrams and equations illustrating a research project conducted at the Swiss Federal Institute of Technology (EPFL) in Lausanne, Switzerland the author describes the first part of his thesis. A new concept of thermally driven heat pump (TDHP) is presented, which could be a real alternative to today's heating systems in buildings that are mainly based on less efficient fuel-fired boilers. Nowadays, the heat pump market is dominated by two kinds of systems: the electrically driven vapor compression heat pumps, which are the most widely used in residential heating applications, and the thermally driven heat pumps that are usually based on a sorption process. In this research project, the investigated TDHP - designated by ORC-ORC - is based on the coupling of a vapor compression heat pump cycle and an organic Rankine cycle (ORC). The studied concept uses a single stage centrifugal compressor directly coupled to a single stage radial inflow turbine. The shaft is rotating on gas bearings, which allows the system to be oil-free. Like most of the other TDHP's, this system has the advantage to work with a variety of fuels or heat sources like wood pellets, natural gas, solar heat, geothermal heat or waste heat. The concept studied in this work is a gas fired system for space heating and domestic hot water production in small residential buildings (power range: 20 kW). A systematic approach has been used to theoretically evaluate, in terms of energy efficiency, the potential of ORC-ORC systems. The method is based on the optimization which allows identifying the best configurations at each design step with respect to the designer choices. This approach is divided into three steps. In the first step, a model of the complete system has been developed based on a process integration approach. This step allows to quickly determine whether the system is potentially attractive or not, for given conditions, before going deeper into

  9. Building a secondary containment system

    Energy Technology Data Exchange (ETDEWEB)

    Broder, M.F.

    1994-10-01

    Retail fertilizer and pesticide dealers across the United States are installing secondary containment at their facilities or are seriously considering it. Much of this work is in response to new state regulations; however, many dealers not facing new regulations are upgrading their facilities to reduce their liability, lower their insurance costs, or comply with anticipated regulations. The Tennessee Valley Authority`s (TVA) National Fertilizer and Environmental Research Center (NFERC) has assisted dealers in 22 states in retrofitting containment to their facilities. Simultaneous improvements in the operational efficiency of the facilities have been achieved at many of the sites. This paper is based on experience gained in that work and details the rationale used in planning secondary containment and facility modifications.

  10. A gas secondary electron detector

    CERN Document Server

    Drouart, A; Alamanos, N; Auger, F; Besson, P; Bougamont, E; Bourgeois, P; Lobo, G; Pollacco, E C; Riallot, M

    2002-01-01

    A new Secondary Electron gas Detector (SED) is under development to be used in conjunction with an emissive foil to detect low energy heavy ions as an alternative to micro-channel plates. It could measure position and time of flight. Secondary electrons are accelerated to 10 keV so that they can cross through the 0.9 mu m Mylar entrance window. The electrons then are multiplied in the isobutane gas of the detector at 4-10 Torr. A time resolution of 150 ps and a spatial resolution of 3 mm have been obtained by using californium fission fragments on a prototype detector of 7x7 cm sup 2. The advantage of the SED against MCP is that its size is not limited. Our final goal is to build a large size detector (15x40 cm sup 2) that will operate at the focal plane of the VAMOS magnetic spectrometer at GANIL.

  11. Utilization of Information and Communication Technologies as a Predictor of Educational Stress on Secondary School Students

    Science.gov (United States)

    Eskicumali, Ahmet; Arslan, Serhat; Demirtas, Zeynep

    2015-01-01

    The purpose of this study is to examine the relationship between utilization of information and communication technologies and educational stress. Participants were 411 secondary school students. Educational Stress Scale and Utilization of Information and Communication Technologies Scale were used as measures. The relationships between students'…

  12. The development and validation of a scale measuring teacher autonomous behaviour

    NARCIS (Netherlands)

    Evers, Arnoud; Verboon, Peter; Klaeijsen, Andrea

    2018-01-01

    In the current study a multi-dimensional scale that measures teacher autonomous behaviour is presented. The scale is applicable across the following educational sectors: primary education, secondary education and vocational education. Based on an elaborate literature study, four theoretically

  13. Secondary middle turbinate: case report

    Energy Technology Data Exchange (ETDEWEB)

    Aburjeli, Bruna de Oliveira Melim; Avila, Ana Flavia Assis de; Diniz, Renata Lopes Furletti Caldeira; Motta, Emilia Guerra Pinto Coelho; Ribeiro, Marcelo Almeida; Moreira, Wanderval, E-mail: bruninha86@hotmail.com [Radiology and Imaging Diagnosis, Hospital Mater Dei, Belo Horizonte, MG (Brazil)

    2012-11-15

    Secondary middle turbinate is an anatomical variant rarely observed in the nasal cavity, firstly described by Khanobthamchai et al. as a bone structure originating from the lateral nasal wall and covered by soft tissue. In most cases reported in the literature, this variant is bilateral, occurring without associated complications. In the present report, the authors describe the case of patient of their institution with such anatomical variation. (author)

  14. Monoparesis secondary to herpes zoster.

    LENUS (Irish Health Repository)

    Bilal, S

    2011-06-01

    We describe a 90-year-old woman with right upper limb monoparesis secondary to varicella zoster virus infection as a result of extensive inflammatory involvement of the entire brachial plexus at root level. To our knowledge, this is the first report of entire brachial plexus involvement in a living patient of such advanced age. Despite a delay in presentation and thus initiation of treatment, a favourable clinical response was observed.

  15. Convergence palsy secondary to amoxicillin.

    Science.gov (United States)

    Pérez-Roca, F; Alfaro Juárez, A; Sánchez Merino, C; Navarro Mingorance, A

    2016-12-01

    We present the case of an 11-year-old boy with acute diplopia in near vision secondary to transient convergence palsy, possibly in relation to amoxicillin. Convergence palsy is an uncommon eye disorder. The causes are reviewed, and amoxicilin is identified as presumptive etiologic agent. This is the first case reported. Copyright © 2016 Sociedad Española de Oftalmología. Publicado por Elsevier España, S.L.U. All rights reserved.

  16. Amblyopia secondary to iris cyst.

    Science.gov (United States)

    López-Arroquia, T E; Avendaño-Cantos, E M; Mesa-Varona, D; Gálvez-Martínez, J; López-Romero, S; Nuñez-Plascencia, R; González del Valle, F

    2014-12-01

    A 5 year-old child diagnosed with moderate anisometropic amblyopia secondary to primary cyst of iris pigment epithelium. He was evaluated with ultrasound biomicroscopy (BMU) and optical coherence tomography (OCT) of anterior segment. The OCT, although with some limitations, is a useful tool to study the anterior segment. It is probably more recommendable than BMU in the childhood. Copyright © 2012 Sociedad Española de Oftalmología. Published by Elsevier Espana. All rights reserved.

  17. Secondary Electrons in EUV Lithography

    Energy Technology Data Exchange (ETDEWEB)

    Torok, Justin; Re, Ryan Del; Herbol, Henry; Das, Sanjana; Bocharova, Irina; Paolucci, Angela; Ocola, Leonidas E.; Ventrice Jr., Carl; Lifshin, Eric; Denbeaux, Greg; Brainard, Robert L.

    2013-01-01

    Secondary electrons play critical roles in several imaging technologies, including extreme ultraviolet (EUV) lithography. At longer wavelengths of light (e.g. 193 and 248 nm), the photons are directly involved in the photochemistry occurring during photolysis. EUV light (13.5 nm, 92 eV), however, first creates a photoelectron, and this electron, or its subsequent daughter electrons create most of the chemical changes that occur during exposure. Despite the importance of these electrons, the details surrounding the chemical events leading to acid production remain poorly understood. Previously reported experimental results using high PAG-loaded resists have demonstrated that up to five or six photoacids can be generated per incident photon. Until recently, only electron recombination events were thought to play a role in acid generation, requiring that at least as many secondary electrons are produced to yield a given number of acid molecules. However, the initial results we have obtained using a Monte Carlo-based modeling program, LESiS, demonstrate that only two to three secondary electrons are made per absorbed EUV photon. A more comprehensive understanding of EUV-induced acid generation is therefore needed for the development of higher performance resists

  18. Secondary Metabolites from Higher Fungi.

    Science.gov (United States)

    Chen, He-Ping; Liu, Ji-Kai

    Secondary metabolites of higher fungi (mushrooms) are an underexplored resource compared to plant-derived secondary metabolites. An increasing interest in mushroom natural products has been noted in recent years. This chapter gives a comprehensive overview of the secondary metabolites from higher fungi, with 765 references highlighting the isolation, structure elucidation, biological activities, chemical syntheses, and biosynthesis of pigments, nitrogen-containing compounds, and terpenoids from mushrooms. Mushroom toxins are also included in each section.In a section on pigments of higher fungi, pigments are classified into four categories, namely, those from the shikimate-chorismate, acetate-malonate, and mevalonate biosynthetic pathways, and pigments containing nitrogen, with 145 references covering the years 2010-2016.In a section on other nitrogen-containing compounds of higher fungi, compounds are categorized primarily into nitrogen heterocycles, nucleosides, non-protein amino acids, cyclic peptides, and sphingolipids, with 65 references covering the years 2010-2016. In turn, in a section describing terpenoids of higher fungi, the sesquiterpenoids and diterpenoids are thoroughly elaborated, spanning the years 2001-2016, and 2009-2016, respectively. The divergent biosynthetic pathways from farnesyl pyrophosphate to sesquiterpenoids are also described. Selected triterpenoids with novel structures and promising biological activities, including lanostanes and ergostanes, are reported from the genus Ganoderma, and the fungi Antrodia cinnamomea and Poria cocos. In addition, cucurbitanes and saponaceolides are also compiled in this section.

  19. Complex modification of secondary silumins

    Directory of Open Access Journals (Sweden)

    A. A. Mityayev

    2014-12-01

    Full Text Available Purpose. Development of scientific and technological bases of formation of the specified secondary hypoeutectic (АK8M3 and eutectic (АК12М2MgН silumins' structure; and increasing their mechanical and service properties' indices in the cast state and after heat treatment up to the level of primary alloys. Methodology. Determination of the chemical composition was conducted by spectral analysis on the spark spectrometer «SPECTROLAB» (Germany. Metallographic analysis was performed on the microscopes МIМ-7 and МIМ-8, and also by the high definition metallography method using the raster electronic microscope «JSMT-300» (Japan. Heat treatment of aluminum alloys was carried out applying T1 and T5 modes according to State Standard of Ukraine 2839-94 (GOST 1583-93. Standard techniques were used during the determination of mechanical properties. The temperature coefficient of linear expansion for the piston alloy АK12М2МgH (AL25 was determined using the specimens Ø with the diameter of 3.5 mm and length of 50 mm with the use of Shevenard optical quartz dilatometer. High temperature fracture resistance was determined according to State Standard 10145-81 as the time before fracture of the specimen at specified stress of 50 MPa and temperature of 300°С. Findings. The technology of obtaining alloys from charge, which consists of 100 % scrap and production wastes has been developed and implemented into production. This technology provides obtaining of metal of the guaranteed chemical composition and high quality with the reduction of energy costs for melting. Originality. The regularities of the formation of the structural and phase state and the level of physical and mechanical properties of eutectic and secondary hypoeutectic silumins depending on the refining and modifying processes have been established. The generalization of regularities of the secondary silumins' fracture has been carried out. Quantitative characteristics of the

  20. Prevalence of urinary schistosomiasis among secondary school ...

    African Journals Online (AJOL)

    Prevalence of urinary schistosomiasis among secondary school students in Ibadan, Nigeria. ... The inclusion of health education package aimed at changing behavior of school children from adverse water contact practices was recommended. Keywords: prevalence, urinary schistosomiasis, secondary school students.

  1. Secondary effects of glyphosate on plants

    Science.gov (United States)

    Glyphosate is a unique herbicide with interesting secondary effects. Unfortunately, some have assumed that the secondary effects that occur in glyphosate-susceptible plants treated with glyphosate, such as altered mineral nutrition, reduced phenolic compound production and pathogen resistance, also ...

  2. Secondary Analysis for Results Tracking Database

    Data.gov (United States)

    US Agency for International Development — The Secondary Analysis and Results Tracking (SART) activity provides support for the development of two databases to manage secondary and third-party data, data...

  3. Secondary Containers and Service Containers for Pesticides

    Science.gov (United States)

    Secondary containers and service containers are used by pesticide applicators in the process of applying a pesticide. EPA does not require secondary containers or service containers to be labeled or to meet particular construction standards. Learn more.

  4. Ergonomics and safety in secondary wood processing

    Science.gov (United States)

    Rado Gazo; James D. McGlothlin; Yuehwern, Wiedenbeck, Jan Yih; Yuehwern Yih

    2002-01-01

    The main goal of the project was to initiate a pilot program in ergonomics for the secondary wood products industry. Case studies were conducted at three Midwest secondary wood product companies in 2000 and 2001.

  5. Secondary Highway Lines, US, 2015, NAVTEQ

    Data.gov (United States)

    U.S. Environmental Protection Agency — NAVTEQ Secondary Highways for the United States. The Secondary Highways layer contains Road Network features based on the Functional Class value on each link present...

  6. Partnership between Teacher Education Institutes and Secondary ...

    African Journals Online (AJOL)

    The data analyzed suggests that the partnership between teacher education institutes and secondary schools is weak and TEIs, secondary schools, student teachers, TEI instructors and secondary school teachers' contribution and supports to each other are not found to be satisfactory. In addition, the evidences suggest that ...

  7. Secondary Trauma in Children and School Personnel

    Science.gov (United States)

    Motta, Robert W.

    2012-01-01

    A review of childhood secondary trauma is presented. Secondary trauma involves the transfer and acquisition of negative affective and dysfunctional cognitive states due to prolonged and extended contact with others, such as family members, who have been traumatized. As such, secondary trauma refers to a spread of trauma reactions from the victim…

  8. Prevalence of alcohol consumption among secondary school ...

    African Journals Online (AJOL)

    Background: Consumption of alcohol by secondary school students is a major public health concern globally, but its prevalence is not known in secondary schools in Port Harcourt. Objective: To determine the prevalence and factors associated with alcohol use among secondary school students in Port Harcourt. Methods: ...

  9. 40 CFR 133.102 - Secondary treatment.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 21 2010-07-01 2010-07-01 false Secondary treatment. 133.102 Section... TREATMENT REGULATION § 133.102 Secondary treatment. The following paragraphs describe the minimum level of effluent quality attainable by secondary treatment in terms of the parameters—BOD5, SS and pH. All...

  10. Assessment of secondary aluminum reserves of nations

    DEFF Research Database (Denmark)

    Maung, Kyaw Nyunt; Yoshida, Tomoharu; Liu, Gang

    2017-01-01

    A classification framework of the secondary resources was applied to evaluate the framework's applicability and to assess secondary aluminum reserves for 19 countries. Estimated amounts of secondary aluminum reserves in 2010 were 85 million tonnes in the United States, 65 million tonnes in China,...

  11. [Inherited primitive and secondary polycythemia].

    Science.gov (United States)

    Barba, T; Boileau, J-C; Pasquet, F; Hot, A; Pavic, M

    2016-07-01

    Myeloproliferative disorders and secondary polycythemia cover most of the polycythemia cases encountered in daily practice. Inherited polycythemias are rare entities that have to be suspected when the classical causes of acquired polycythemia have been ruled out. Recent advances were made in the understanding of these pathologies, which are still little known to the physicians. This review reports the state of knowledge and proposes an algorithm to follow when confronted to a possible case of inherited polycythemia. Copyright © 2015 Société Nationale Française de Médecine Interne (SNFMI). Published by Elsevier SAS. All rights reserved.

  12. Prediction of secondary sonic boom

    Science.gov (United States)

    Kaouri, K.; Allwright, D. J.; Dellar, P. J.

    2003-04-01

    Many studies on primary sonic boom have been conducted, but not much is known about secondary boom. The primary boom leaves the aircraft in the downward direction and is felt on the ground as a rapid change in pressure over less than one second. Secondary boom leaves the aircraft in the upward direction but is then ``reflected'' downwards due to inhomogeneities and/or wind in the upper atmosphere. It therefore reaches the ground a few minutes after the primary boom. Data from Concorde show that the primary and secondary boom signatures are very different. The most likely reason for these differences is the much longer distance involved in the secondary boom propagation. Through detailed mathematical modelling and asymptotic methods we first quantify the underlying physical mechanicms such as nonlinearity, earth rotation, curvature, relaxation effects, viscous dissipation etc., and we show when the short-range approximations used for primary boom are no longer applicable. As a model problem, we consider steady supersonic flight of a slender aircraft in a spatially varying atmosphere. Starting from the linearised Euler equations and the stratified sound speed profile c=c_0/√{1-bz}, we calculate analytically the surface of influence of the boom in the air and on the ground. The geometry of this surface is very important because folds in it indicate places of increased boom intensity. To calculate the boom intensity, ray theory (a short-wave approximation) has been employed by previous authors, but this yields infinite amplitudes at folds. We follow a more detailed semi-analytical approach that yields a finite wavefield in the whole domain. We expect the same qualitative behaviour in more complicated realistic atmospheres, even though the calculation can usually only be completed numerically. To further refine the location and intensity of the boom we retain nonlinear effects. Using the method of matched asymptotic expansions, we derive a weakly nonlinear model for

  13. The secondary metabolite bioinformatics portal

    DEFF Research Database (Denmark)

    Weber, Tilmann; Kim, Hyun Uk

    2016-01-01

    . In this context, this review gives a summary of tools and databases that currently are available to mine, identify and characterize natural product biosynthesis pathways and their producers based on ‘omics data. A web portal called Secondary Metabolite Bioinformatics Portal (SMBP at http......://www.secondarymetabolites.org) is introduced to provide a one-stop catalog and links to these bioinformatics resources. In addition, an outlook is presented how the existing tools and those to be developed will influence synthetic biology approaches in the natural products field....

  14. Secondary emission monitor (SEM) grids.

    CERN Multimedia

    Patrice Loïez

    2002-01-01

    A great variety of Secondary Emission Monitors (SEM) are used all over the PS Complex. At other accelerators they are also called wire-grids, harps, etc. They are used to measure beam density profiles (from which beam size and emittance can be derived) in single-pass locations (not on circulating beams). Top left: two individual wire-planes. Top right: a combination of a horizontal and a vertical wire plane. Bottom left: a ribbon grid in its frame, with connecting wires. Bottom right: a SEM-grid with its insertion/retraction mechanism.

  15. Lymphadenopathy secondary to lamotrigine (Lamictal).

    Science.gov (United States)

    Marraffa, Jeanna M; Guharoy, Roy

    2002-10-01

    We report lymphadenopathy in a 5-yo-female most likely secondary to lamotrigine. Lamotrigine is effective in the treatment of partial and generalized seizure disorders and often prescribed by neurologists and pediatricians because of its effectiveness in children with idiopathic, resistant generalized seizure disorders; it lacks cognitive impairment. Lamotrigine's chemical structure contains an aromatic ring and is similar to phenytoin, carbamazepine and phenobarbital. The patient had a documented drug allergy to both phenytoin and carbamazepine, and clinically improved following discontinuation of the lamotrigine. Clinicians should be aware of this potential adverse event for patients treated with lamotrigine.

  16. Secondary flows in turbulent boundary layers over longitudinal surface roughness

    Science.gov (United States)

    Hwang, Hyeon Gyu; Lee, Jae Hwa

    2018-01-01

    Direct numerical simulations of turbulent boundary layers over longitudinal surface roughness are performed to investigate the impact of the surface roughness on the mean flow characteristics related to counter-rotating large-scale secondary flows. By systematically changing the two parameters of the pitch (P) and width (S) for roughness elements in the ranges of 0.57 ≤P /δ ≤2.39 and 0.15 ≤S /δ ≤1.12 , where δ is the boundary layer thickness, we find that the size of the secondary flow in each case is mostly determined by the value of P - S, i.e., the valley width, over the ridge-type roughness. However, the strength of the secondary flows on the cross-stream plane relative to the flow is increased when the value of P increases or when the value of S decreases. In addition to the secondary flows, additional tertiary and quaternary flows are observed both above the roughness crest and in the valley as the values of P and S increase further. Based on an analysis using the turbulent kinetic energy transport equation, it is shown that the secondary flow over the ridge-type roughness is both driven and sustained by the anisotropy of turbulence, consistent with previous observations of a turbulent boundary layer over strip-type roughness [Anderson et al., J. Fluid Mech. 768, 316 (2015), 10.1017/jfm.2015.91]. Careful inspection of the turbulent kinetic energy budget reveals that the opposite rotational sense of the secondary flow between the ridge- and strip-type roughness elements is primarily attributed to the local imbalance of energy budget created by the strong turbulent transport term over the ridge-type roughness. The active transport of the kinetic energy over the ridge-type roughness is closely associated with the upward deflection of spanwise motions in the valley, mostly due to the roughness edge.

  17. Prediction of secondary structural content of proteins from their amino acid composition alone. II. The paradox with secondary structural class.

    Science.gov (United States)

    Eisenhaber, F; Frömmel, C; Argos, P

    1996-06-01

    The success rates reported for secondary structural class prediction with different methods are contradictory. On one side, the problem of recognizing the secondary structural class of a protein knowing only its amino acid composition appears completely solved by simply applying jury decision with an elliptically scaled distance function. Chou and coworkers repeatedly (see Crit. Rev. Biochem. Mol. Biol. 30:275-349, 1995) published prediction accuracies near 100%. On the other hand, traditional secondary structure prediction techniques achieve success rates of about 70% for the secondary structural state per residue and about 75% for structural class only with extensive input information (full sequence of the query protein, its amino acid composition and length, multiple alignments with homologous sequences). In this article, we resolve the paradox and consider (1) the question of the secondary structural class definition, (2) the role of the representativity of the test set of protein tertiary structure for the current state of the Protein Data Bank (PDB); and (3) we estimate the real impact of amino acid composition on secondary structural class. We formulate three objective criteria for a reasonable definition of secondary structural classes and show that only the criterion of Nakashima et al. (J. Biochem. 99:153-162, 1986) complies with all of them. Only this definition matches the distribution of secondary structural content in representative PDB subsets, whereas other criteria leave many proteins (up to 65% of all PDB entries) simply unassigned. We review critically specialized secondary-structural class prediction methods, especially those of Chou and coworkers, which claim almost 100% accuracy using only amino acid composition, and resolve the paradox that these prediction accuracies are better than those from secondary structure predictions from multiple alignments. We show (i) that these techniques rely on a preselection of test sets which removes

  18. [Secondary malignancies in urinary diversions].

    Science.gov (United States)

    Kälble, T; Hofmann, I; Thüroff, J W; Stein, R; Hautmann, R; Riedmiller, H; Vergho, D; Hertle, L; Wülfing, C; Truß, M; Roth, S; von Rundstedt, F C; Albers, P; Gschwend, J; Herkommer, K; Humke, U; Spahn, M; Bader, P; Steffens, J; Harzmann, R; Stief, C G; Karl, A; Müller, S C; Waldner, M; Noldus, J; Kleinschmidt, K; Alken, P; Kopper, B; Fisch, M; Lampel, A; Stenzel, A; Fichtner, J; Flath, B; Rübben, H; Juenemann, K P; Hautmann, S; Knipper, A; Leusmann, D; Strohmaier, W; Thon, W F; Miller, S; Weingärtner, K; Schilling, A; Piechota, H; Becht, J E; Schwaibold, H; Bub, P; Conrad, S; Wenderoth, U; Merkle, W; Rösch, W; Otto, T; Ulshöfer, B; Westenfelder, M

    2012-04-01

    In contrast to ureterosigmoidostomy no reliable clinical data exist for tumor risk in different forms of urinary diversion using isolated intestinal segments.In 44 German urological departments, operation frequencies, indications, patient age, and operation dates of the different forms of urinary diversion, operated between 1970 and 2007, could be registered. The secondary tumors up to 2009 were registered as well and related to the numbers of the different forms of urinary diversions resulting in tumor prevalences.In 17,758 urinary diversions 32 secondary tumors occurred. The tumor risk in ureterosigmoidostomy (22-fold) and cystoplasty (13-fold) is significantly higher than in other continent forms of urinary diversion such as neobladders or pouches (p<0.0001). The difference between ureterosigmoidostomy and cystoplasty is not significant, nor is the difference between ileocecal pouches (0.14%) and ileal neobladders (0.05%) (p=0.46). The tumor risk in ileocecal (1.26%) and colonic neobladders (1.43%) is significantly higher (p=0.0001) than in ileal neobladders (0.5%). Of the 16 tumors that occurred following ureterosigmoidostomy, 16 (94%) developed directly at the ureterocolonic borderline in contrast to only 50% following urinary diversions via isolated intestinal segments.From postoperative year 5 regular endoscopic controls of ureterosigmoidostomies, cystoplasties, and orthotopic (ileo-)colonic neobladders are necessary. In ileocecal pouches, regular endoscopy is necessary at least in the presence of symptoms or should be performed routinely at greater intervals. Following neobladders or conduits, only urethroscopies for urethral recurrence are necessary.

  19. Nant-De-Chatillon: electric power generation by ORC (organic Rankine cycle) using waste heat from the Chatillon biogas plant; Nant-de-Chatillon: Production d'electricite par ORC a partir des rejets de chaleur du site de methanisation de Chatillon. Resume

    Energy Technology Data Exchange (ETDEWEB)

    Kane, M.; Gay, B.

    2005-07-01

    This report prepared for the Swiss Federal Office of Energy (SFOE) describes the practical realisation and testing of a heat recovery system based on a one-stage organic Rankine cycle with R134a as the working fluid. The waste heat has a temperature of 95 {sup o}C and originates from a gas engine that powers a small co-generation plant fuelled with biogas produced on-site. Two similar cycles have been built, ORC1 with one and ORC2 with two turbines. Only ORC1 has been tested so far. The maximum efficiency measured in these tests was 6.64% (theoretical Carnot-efficiency: 17 %) and the electric power output was 5.0 kW. The problems encountered during commissioning are described and recommendations for further improvements are given.

  20. Secondary hyperalgesia to heat stimuli after burn injury in man

    DEFF Research Database (Denmark)

    Pedersen, J L; Kehlet, H

    1998-01-01

    ), and assessments were made 70 min and 40 min before, and 0, 1, and 2 h after the burn injury. Hyperalgesia to mechanical and heat stimuli were examined by von Frey hairs and contact thermodes (3.75 and 12.5 cm2), and pain responses were rated with a visual analog scale (0-100). The area of secondary hyperalgesia......The aim of the study was to examine the presence of hyperalgesia to heat stimuli within the zone of secondary hyperalgesia to punctate mechanical stimuli. A burn was produced on the medial part of the non-dominant crus in 15 healthy volunteers with a 50 x 25 mm thermode (47 degrees C, 7 min...... to punctate stimuli was assessed with a rigid von Frey hair (462 mN). The heat pain responses to 45 degrees C in 5 s (3.75 cm2) were tested in the area just outside the burn, where the subjects developed secondary hyperalgesia, and on the lateral crus where no subject developed secondary hyperalgesia (control...

  1. ORC-mall scale power plant

    Energy Technology Data Exchange (ETDEWEB)

    Jokinen, T. [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Electromechanics

    1998-12-31

    In the conversion of low temperature heat into electricity, the greatest efficiency is obtained by using a Rankine cycle. The Organic Rankine cycle (ORC) is a Rankine cycle where an organic fluid is used instead of water as the working fluid. In the conventional ORC-solution, an axial turbine drives a standard generator through a high-speed gearbox. The system includes a separate feed pump, vacuum pump, lubrication system and requires several saft seals. The seals of the turbine have a limited working life in particular due to the high speed required. Thus, the entire present conventional ORC-plant is rather complicated and requires maintenance. To avoid these problems, a project was initiated at the Lappeenranta University of Technology to develop a high-speed, process fluid lubricated turbogenerator-feed pump as the prime mover of the ORC. The project has been continued in co-operation with the Helsinki University of Technology under the NEMO 2 program, the main goal being to build a demonstration power plant and to commercialise the project. The goals of the project were: (1) to model the ORC process, turbogenerator, and inverter, (2) to simulate the power plant in different normal and abnormal states, (3) to assess the advantages and disadvantages of various control systems, (4) to study network disturbances such as voltage and current harmonics and to research ways of reducing these disturbances, (5) to optimise heat exchanging surfaces and process parameters, and (6) to participate in the design of the demonstration power plant

  2. Combinatorics of saturated secondary structures of RNA.

    Science.gov (United States)

    Clote, P

    2006-11-01

    Following Zuker (1986), a saturated secondary structure for a given RNA sequence is a secondary structure such that no base pair can be added without violating the definition of secondary structure, e.g., without introducing a pseudoknot. In the Nussinov-Jacobson energy model (Nussinov and Jacobson, 1980), where the energy of a secondary structure is -1 times the number of base pairs, saturated secondary structures are local minima in the energy landscape, hence form kinetic traps during the folding process. Here we present recurrence relations and closed form asymptotic limits for combinatorial problems related to the number of saturated secondary structures. In addition, Python source code to compute the number of saturated secondary structures having k base pairs can be found at the web servers link of bioinformatics.bc.edu/clotelab/.

  3. Complex regional pain syndrome secondary to leprosy.

    Science.gov (United States)

    Ghia, Deepti; Gadkari, Reshma; Nayak, Chitra

    2012-08-01

    Leprosy is a chronic infectious disease caused by Mycobacterium leprae affecting the skin and the nerves. Complex regional pain syndrome (CRPS/Sudeck's dystrophy) is a painful and disabling condition--a triad of autonomic, sensory, and motor symptoms disproportionate to the inciting event (inflammatory, infective, or traumatic nerve damage). A 20-year-old male presented with continuous pain, aggravated by cold and emotions, loss of fine touch and temperature sensation, redness, swelling, along lateral aspect of left hand and forearm with weakness in the grip of 6 months' duration. There was a 5-year history of sensory loss only over left index finger that he ignored. Examination revealed abnormal sensory and autonomic functions along left radial and median nerve distribution that were confirmed by nerve conduction studies suggestive of mononeuritis multiplex. Radial cutaneous nerve biopsy was suggestive of leprosy. Magnetic resonance imaging and ultrasonography showed no compressive etiology; however, MRI showed involvement of brachial plexus. Antileprosy, anti-inflammatory drugs, and steroids were given in view of neuritis because of lepra reaction with supportive measures of physiotherapy, transcutaneous electrical nerve stimulation, to no avail. A surgical median nerve decompression also failed to relieve the pain. Temporary stellate ganglion block improved the pain scale. Thus, excluding all other causes, the final diagnosis was CRPS secondary to leprosy. There is only one reported case of CRPS with leprosy. Leprous neuropathy caused the nerve damage that lead to CRPS type 2. Very rarely leprosy can lead to CRPS. CRPS is a diagnosis of exclusion. Wiley Periodicals, Inc.

  4. Anxiety, Self-Esteem and Coping with Stress in Secondary School Students in Relation to Involvement in Organized Sports

    OpenAIRE

    Dolenc Petra

    2015-01-01

    Aim The objective of the study was to examine self-esteem, anxiety level and coping strategies among secondary school students in relation to their involvement in organized sports. Methods The sample included 280 Slovenian male and female secondary school students aged between 15 and 19 years. The participants completed The Adolescent Coping Scale, the Spielberger State-Trait Anxiety Inventory, and the PSDQ Selfesteem Scale. Results Participants engaged in organized sports exhibited higher se...

  5. Feasibility Study of Secondary Heat Exchanger Concepts for the Advanced High Temperature Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Piyush Sabharwall

    2011-09-01

    The work reported herein represents a significant step in the preliminary design of heat exchanger options (material options, thermal design, selection and evaluation methodology with existing challenges). The primary purpose of this study is to aid in the development and selection of the required heat exchanger for power production using either a subcritical or supercritical Rankine cycle.

  6. Extraction of plant secondary metabolites.

    Science.gov (United States)

    Jones, William P; Kinghorn, A Douglas

    2012-01-01

    This chapter presents an overview of the preparation of extracts from plants using organic solvents, with emphasis on common problems encountered and methods for their reduction or elimination. In addition to generally applicable extraction protocols, methods are suggested for selectively extracting specific classes of plant-derived compounds, and phytochemical procedures are presented for the detection of classes of compounds encountered commonly during extraction, including selected groups of secondary metabolites and interfering compounds. Successful extraction begins with careful selection and preparation of plant samples and thorough review of the appropriate literature for suitable protocols for a particular class of compounds or plant species. During the extraction of plant material, it is important to minimize interference from compounds that may co-extract with the target compounds, and to avoid contamination of the extract, as well as to prevent decomposition of important metabolites or artifact formation as a result of extraction conditions or solvent impurities.

  7. Secondary avalanches in gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Şahin, Özkan, E-mail: osahin@uludag.edu.tr [Department of Physics, Uludağ University, 16059 Bursa (Turkey); Tapan, İlhan [Department of Physics, Uludağ University, 16059 Bursa (Turkey); Veenhof, Rob [RD51 Collaboration, CERN, Genève (Switzerland)

    2013-08-01

    Avalanche development in gas-based detectors relies not only on direct ionisation but also on excitation of noble gas atoms. Some quencher molecules can be ionised when they collide with excited atoms, a process on which we reported earlier [1]. Alternatively, excited atoms can decay by photon emission. If these photons are insufficiently absorbed by the quencher, yet capable of ionising, then they may escape from the avalanche region and start secondary avalanches. This process, called photon feedback, leads to an over-exponential increase of the gas gain which limits the working range. In this paper, we derive photon feedback parameters from published gain measurements for several gas mixtures and fit these parameters in a model which describes their dependence on the quencher concentration and the pressure.

  8. Flame tolerant secondary fuel nozzle

    Science.gov (United States)

    Khan, Abdul Rafey; Ziminsky, Willy Steve; Wu, Chunyang; Zuo, Baifang; Stevenson, Christian Xavier

    2015-02-24

    A combustor for a gas turbine engine includes a plurality of primary nozzles configured to diffuse or premix fuel into an air flow through the combustor; and a secondary nozzle configured to premix fuel with the air flow. Each premixing nozzle includes a center body, at least one vane, a burner tube provided around the center body, at least two cooling passages, a fuel cooling passage to cool surfaces of the center body and the at least one vane, and an air cooling passage to cool a wall of the burner tube. The cooling passages prevent the walls of the center body, the vane(s), and the burner tube from overheating during flame holding events.

  9. Pulmonary involvement of secondary syphilis.

    Science.gov (United States)

    Ogawa, Yoshihiko; Imai, Yuichiro; Yoshihara, Shingo; Fujikura, Hiroyuki; Hirai, Nobuyasu; Sato, Masatoshi; Ogawa, Taku; Uno, Kenji; Kasahara, Kei; Yano, Hisakazu; Mikasa, Keiichi

    2018-01-01

    Pulmonary involvement in secondary syphilis is considered a rare occurrence; however, the number of cases has increased in the 2000s. This is likely due to the increased use of computed tomography scans and molecular diagnostic testing. We report a case of an HIV-positive man with pleural chest pain and bilateral subpleural nodules on chest computed tomography. His rapid plasma reagin and Treponema pallidum hemagglutination tests were positive, and the specimen of one of the pulmonary nodules obtained by transthoracic biopsy was positive for the polA gene of Treponema pallidum. Since clinical manifestations of syphilis are highly variable, clinicians should bear in mind that pleural chest pain with bilateral subpleural nodules can be caused by pulmonary syphilis.

  10. Pseudoporphyria secondary to renal failure

    Directory of Open Access Journals (Sweden)

    Lilianna Kulczycka-Siennicka

    2017-04-01

    Full Text Available Introduction . Pseudoporphyria is a rare disease associated with chronic renal failure. Symptoms of pseudoporphyria may develop in response to UV exposure and medications. The literature reports cases of pseudoporphyria in patients infected with hepatis C virus, HIV and undergoing dialysis therapy. Objective . Presentation of the case of a patient with pseudoporphyria and uraemic pruritus, and overview of therapeutic management. Case report . A 64-year-old male patient, who had been on dialysis for chronic renal failure secondary to type 2 diabetes for the past 11 years, presented with tense bullae located on sun-exposed skin which had persisted for the previous 5 months. The patient was diagnosed with pseudoporphyria, and treatment was prescribed including N-acetylcysteine, chloroquine, paroxetine and mianserin. An improvement in the patient’s clinical condition and a regression of pruritus were achieved. Conclusions . Patients with renal failure may develop symptoms of pseudoporphyria requiring differentiation from porphyria cutanea tarda.

  11. [Pseudoballism secondary to spinal trauma].

    Science.gov (United States)

    Giménez-Muñoz, A; Alarcia, R; Ledesma, L; Ara, J R

    2008-06-01

    Ballism is a rare movement disorder that presents with violent and wide amplitude flinging movements of the limbs, mainly caused by injury in the contralateral subthalamic nucleus or its afferent or efferent connections. We describe the case of a 50-year old male who had ballistic movements after a cervical trauma. He subsequently developed choreoathetoid movements and a distonic attitude in the left upper limb later. A C2-C3 sensory level and proprioceptive loss in this limb were the main findings in the examination. The cervical magnetic resonance showed a transverse linear spinal lesion at C1 level that affected most of its section. This case stands outs because of the wide abnormal movements spectrum secondary to spinal proprioceptive pathway injury: ballistic, choreoathetoid, and distonic movements. Choreoathetoid movements occurring in association with loss of propioception have been called pseudochoreoathetosis. We propose the term pseudoballism to define the movements that were observed during the acute phase in this patient.

  12. Carbon sequestration capacity and secondary succession in a dry environment

    Science.gov (United States)

    Estruch, Carme; Lozano, Yudi M.; Armas, Cristina; Pugnaire, Francisco I.

    2017-04-01

    Human activities often alter natural plant communities which, after disturbance, undergo a process of secondary succession with important changes in C dynamics. In arid environments this process is very slow, and its links with C cycling are little known. We addressed changes in C balance along a chronosequence of land abandonment in a semiarid environment and assessed the consequences of secondary succession on C sequestration capacity at community scale. We used a closed-chamber method to estimate the daytime contribution of whole-plants and bare soil to whole-community C exchange. Plant community composition and cover strongly affected C balance across the chronosequence. Overall, whole-community C exchange shifted from C source to C sink with succession. However, only after 63 years of agriculture abandonment the system did recover its natural C sequestration capacity. Thus, the capacity of semiarid ecosystems to recover native plant communities after anthropogenic disturbance may contribute to decrease C emissions in the long term.

  13. Translation and validation into Brazilian Portuguese of the Spastic Paraplegia Rating Scale (SPRS

    Directory of Open Access Journals (Sweden)

    Katiane R. Servelhere

    2016-06-01

    Full Text Available ABSTRACT Hereditary spastic paraplegias (HSP are characterized by progressive lower limb weakness and spasticity. There are no validated instruments to quantify disease severity in Portuguese. Objective To translate and validate the Spastic Paraplegia Rating Scale (SPRS into Brazilian-Portuguese. Method Two experienced and English-fluent neurologists translated SPRS into Portuguese, creating SPRS-BR. We then assessed inter and intra-rater reliability of this version using coefficients of correlation and variability in a cohort of 30 patients. Results Mean age of patients and disease duration were 47.7 ± 10.5 and 17.0 ± 10.6 years, respectively. Twenty-one had pure HSP and SPG4 was the most frequent genotype. Mean Rankin and SPRS-BR scores were 2.2 ± 0.9 and 19.9 ± 9.9, respectively. Mean intra and inter-rater correlation coefficients of SPRS-BR scores were 0.951 and 0.934, whereas coefficients of variation were 11.5% (inter-rater and 9.9% (intra-rater. Cronbach’s alpha for the whole SPRS-BR scale was 0.873. Conclusion SPRS-BR is a useful, reliable and valid clinical instrument.

  14. Immersion medicine programme for secondary students.

    Science.gov (United States)

    Minhas, Paras S; Kim, Nathan; Myers, Jayson; Caceres, Wendy; Martin, Marina; Singh, Baldeep

    2017-08-14

    Although the proportion of ethnicities representing under-represented minorities in medicine (URM) in the general population has significantly increased, URM enrolment in medical schools within the USA has remained stagnant in recent years. This study sought to examine the effect of an immersion in community medicine (ICM) programme on secondary school students' desire to enter the field of medicine and serve their communities. The authors asked all 69 ICM alumni to complete a 14-question survey consisting of six demographic, four programme and four career questions, rated on a Likert scale of 1 (completely disagree) to 5 (completely agree), coupled with optional free-text questions. Data were analysed using GraphPad prism and nvivo software. A total of 61 students responded, representing a response rate of 88.4 per cent, with a majority of respondents (73.7%) from URM backgrounds. An overwhelming majority of students agreed (with a Likert rating of 4 or 5) that the ICM programme increased their interest in becoming a physician (n = 56, 91.8%). Students reported shadowing patient-student-physician interactions to be the most useful (n = 60, 98.4%), and indicated that they felt that they would be more likely to lead to serving the local community as part of their future careers (n = 52, 85.3%). Of the students that were eligible to apply to medical school (n = 13), a majority (n = 11, 84.6%) have applied to medical school. URM enrolment in medical schools within the USA has remained stagnant in recent years DISCUSSION: Use of a community medicine immersion programme may help encourage secondary students from URM backgrounds to gain the confidence to pursue a career in medicine and serve their communities. Further examination of these programmes may yield novel insights into recruiting URM students to medicine. © 2017 John Wiley & Sons Ltd and The Association for the Study of Medical Education.

  15. Principles for Enabling Deep Secondary Design

    DEFF Research Database (Denmark)

    Hansen, Magnus Rotvit Perlt; Pries-Heje, Jan

    and techniques in a hospital. Our analysis of the two cases leads to the identification of four principles of design implementation that primary designers can apply to enable secondary design and four corresponding design implementation principles that secondary designers themselves need to apply.......User-based redesign after implementation has been studied in many contexts gone by many different names, such as appropriation of technology, malleable design and secondary design. The phenomenon of redesigning content has mainly revolved around technologies such as Facebook, Twitter, or Wikipedia...... or portal-based technology with configuration abilities, with very little focus on technologies where users can change both functionality, content and the level of technology complexity. We coin this type of secondary design deep secondary design. In this paper, we investigate how to enable deep secondary...

  16. Learner Autonomy Scale: A Scale Development Study

    Science.gov (United States)

    Orakci, Senol; Gelisli, Yücel

    2017-01-01

    The goal of the study is to develop a scale named "Learner Autonomy Scale" (LAS) for determining the learner autonomy of the students toward English lesson. The proposal scale, composed of 29 items, was applied to two study groups in Turkey. The group of Exploratory Factor Analysis that aims to determine the psychometric properties…

  17. Unrecognized and unappreciated secondary causes of osteoporosis.

    Science.gov (United States)

    Miller, Paul D

    2012-09-01

    There are a substantial number of secondary causes of osteoporosis that can be identified through appropriate evaluation. Unrecognized celiac disease, Monoclonal gamopathy of undetermined significance (MGUS), impaired renal function, diabetes mellitus, and renal tubular acidosis are just a few of the more common secondary causes of osteoporosis. Through targeted laboratory tests, many secondary causes of osteoporosis can be identified. Copyright © 2012. Published by Elsevier Inc.

  18. Reading in the junior secondary school phase

    OpenAIRE

    2014-01-01

    M.Ed. The overall concern of this investigation lies in the need to improve secondary school reading performance. This concern is of great importance given the centrality of reading to the English First Language course and to the whole of the secondary school academic curriculum. Poor reading ability is an obstacle to later academic success and, for this reason, it is crucial that each pupil's reading ability and experience is developed as early as possible in the secondary school years. T...

  19. Modelling secondary eclipses of Kepler exoplanets

    Directory of Open Access Journals (Sweden)

    Hambálek Lubomír

    2015-01-01

    Full Text Available We have selected several Kepler objects with potentially the deepest secondary eclipses. By combination of many single phased light-curves (LCs we have produced a smooth LC with a larger SNR and made the secondary eclipses more distinct. This allowed us to measure the depth of primary and secondary minimum with greater accuracy and then to determine stellar and planetary radii by simplex modelling.

  20. A model of the secondary radiation belt

    OpenAIRE

    Selesnick, R. S.; Looper, M. D.; Mewaldt, R. A.

    2008-01-01

    Products of nuclear reactions between primary radiation belt protons and constituents of the tenuous upper atmosphere form a collocated secondary radiation belt. A calculation of the time-dependent secondary intensity provides a model specification of this environmental component for low- and medium-altitude satellite orbits. It is based on an earlier model of the radiation belt protons, the novel feature being a determination of the secondary source function from nuclear reaction cross secti...

  1. ENVIRONMENTAL AWARENESS AMONG SECONDARY SCHOOL STUDENTS

    OpenAIRE

    Dhanya C H; Mrs. Pankajam. R

    2017-01-01

    Environmental awareness is to understand the fragility of our environment and the importance of its protection. Promoting environmental awareness is an easy way to become an environmental steward and participate in creating a brighter future for our children. The study aimed to examine the environmental awareness among secondary school students. The investigator adopted survey method to study the environmental awareness among secondary school students. For this study a sample of 300 secondary...

  2. Intracranial abscess secondary to dental infection

    OpenAIRE

    Brady, Paul; Bergin, Sarah; Cryan, Bartley; Flanagan, Oisin

    2014-01-01

    We report a case of Aggregatibacter actinomycetemcomitans (A.actinomycetemcomitans) bacteraemia and secondary brain abscess in a patient where periodontal disease was implicated as the probable source.

  3. Modeling effects of secondary tidal basins on estuarine morphodynamics

    Science.gov (United States)

    Nnafie, Abdel; Van Oyen, Tomas; De Maerschalck, Bart

    2017-04-01

    Many estuaries are situated in very densely populated areas with high economic activities that often conflict with their ecological values. For centuries, geometry and bathymetry of estuaries have been drastically modified trough engineering works such as embanking, sand extraction, channel deepening, land reclamations, etc. It is generally recognized that these works may increase the tidal range (e.g., Scheldt, Ems, Elbe) and turbidity (e.g., Loire, Ems) in estuaries [cf. Kerner, 2007; Wang et al., 2009; Winterwerp and Wang, 2013; Van Maren et al., 2015b,a]. In recent years, construction of secondary basins (also called retention basins) has gained increasing popularity among coastal managers to reduce tidal range and turbidity [Donner et al., 2012]. Previous studies have shown that location, geometry and number of secondary basins have a significant impact on tidal characteristics and sediment transport [Alebregtse and de Swart, 2014; Roos and Schuttelaars, 2015]. However, knowledge on how these secondary basins affect the morphodynamic development of estuaries on long time scales (order decades to centuries) is still lacking. The specific objectives of this study are twofold. First, to investigate effects of secondary basins on the long-term morphodynamic evolution of estuaries. In particular, effects of the presence of such a basin on the morphodynamic evolution of the main channel in the estuary and the physics underlying channel migration will be examined. For this, the Western Scheldt estuary (situated in the Netherlands) is used as a case study, which used to consist of multiple secondary tidal basins that were located at different positions in the estuary, and which have been gradually closed off between 1800 and 1968. Second, to systematically quantify sensitivity of model results to location, geometry, and to number of secondary basins. To this end, the state-of-the- art numerical model Delft3D is used, which has been successfully applied to

  4. EXAMINING SECONDARY SCHOOL STUDENTS’ ATTITUDES TOWARDS VISUAL ARTS COURSE

    OpenAIRE

    GÜNEŞ, Armağan

    2015-01-01

    Art education is thought to be quite an important factor in helping students find their own selves. Guiding students to help them determine their skills at an early age and to take education in the fields appropriate to their skills is the key to children’s success in their professional lives. The purpose of this study was to determine secondary school students’ attitudes towards Visual Arts Education. In order to collect the research data, “Attitude Scale towards the Course of Art and Drawin...

  5. Secondary neoplasms after stereotactic radiosurgery.

    Science.gov (United States)

    Patel, Toral R; Chiang, Veronica L S

    2014-01-01

    The use of medical radiation has increased 6-fold in the past 30 years. Within neurosurgery, the advent of stereotactic radiosurgery (SRS) has significantly altered the treatment paradigm for both benign and malignant central nervous system diseases. With this increased reliance on radiation has come a responsibility to identify the long-term risks, including the potential development of radiation-induced neoplasms. Although the data regarding traditional radiation exposure and its subsequent risks are well-defined, the data for SRS is less developed. We reviewed the published literature to more accurately define the risk of developing secondary neoplasms after stereotactic radiosurgery. A total of 36 cases of SRS-induced neoplasms were identified. More than half of the cases had an initial diagnosis of vestibular schwannoma. Overall, the risk of developing an SRS-induced neoplasm is approximately 0.04% at 15 years. The risk of developing an SRS-induced neoplasm is low but not zero. Thus, long-term surveillance imaging is advised for patients treated with SRS. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Secondary anchor targeted cell release.

    Science.gov (United States)

    Ansari, Ali; Lee-Montiel, Felipe T; Amos, Jennifer R; Imoukhuede, P I

    2015-11-01

    Personalized medicine offers the promise of tailoring therapy to patients, based on their cellular biomarkers. To achieve this goal, cellular profiling systems are needed that can quickly and efficiently isolate specific cell types without disrupting cellular biomarkers. Here we describe the development of a unique platform that facilitates gentle cell capture via a secondary, surface-anchoring moiety, and cell release. The cellular capture system consists of a glass surface functionalized with APTES, d-desthiobiotin, and streptavidin. Biotinylated mCD11b and hIgG antibodies are used to capture mouse macrophages (RAW 264.7) and human breast cancer (MCF7-GFP) cell lines, respectively. The surface functionalization is optimized by altering assay components, such as streptavidin, d-desthiobiotin, and APTES, to achieve cell capture on 80% of the functionalized surface and cell release upon biotin treatment. We also demonstrate an ability to capture 50% of target cells within a dual-cell mixture. This engineering advancement is a critical step towards achieving cell isolation platforms for personalized medicine. © 2015 Wiley Periodicals, Inc.

  7. Secondary structure of synthetic oligopeptides

    CERN Document Server

    Martinez-Insua, M

    2000-01-01

    The secondary structure of three hydrophobic peptides P2, PRMo and P4 was studied by a combination of Circular Dichroism (CD), Fourier Transform InfraRed (FTIR) and Photoinduced Electron Transfer (PET). These peptides were fluorescence labelled in the central part of the backbone and contained two modified glutamic acid residues (relative positions i, i+4): one conjugated with the fluorescence methoxynapththalene electron donor (DON) and the other with the piperidone electron acceptor (ACC). The three peptides were synthesised to study the length dependence of the switch between alpha-helix and the 3 sub 1 sub 0 -helix conformations, previously observed for peptide PRM1 (Hungerford et al., Angew. Chem., Int. Ed. Engl., 1996, 35, 326-329). The CD and FTIR data indicated that peptides P2, PRMo and P4 adopt alpha-helical conformation in organic media in the temperature range studied and no conformational switch was detected. Furthermore, a mathematical correlation was observed in the PET data, questioning the ag...

  8. Biomass fired small-scale CHP technologies - Present status and possibilities

    Energy Technology Data Exchange (ETDEWEB)

    Konttinen, J. (Univ. of Jyvaeskylae, Jyvaeskylae (Finland), Renewable energy programme), e-mail: jukontti@jyu.fi; Linna, V. (VTT Technical Research Centre of Finland, Jyvaeskylae (Finland)), e-mail: veli.linna@vtt.fi; Uusi-Maahi, I. (Keulink Oy, Keuruu (Finland)), e-mail: ilkka.uusi-maahi@keulink.fi

    2010-07-01

    The competitiveness of biomass-fuelled CHP (Combined Heat and Power) production technologies is rising. Small-scale (or micro-CHP) means power and heat production in the scale of 10...1000 kW{sub e} by combustion or gasification of biomass. A survey about the commercial potential and technologies in Europe of micro-CHP was made by the University of Jyvaeskylae and VTT (Technical Research Centre of Finland). The survey was funded by Keulink Oy and Jyvaeskylae Innovation Oy. According to the results of the literature survey, the most promising technologies for power production are based on so called ORC (Organic Rankine Cycle) and Stirling engines. Woody-type of biomass is the best raw material for these applications. With the small-scale technologies, the power production efficiency can vary in the range of 15...30 % of the biomass thermal input. New innovative technologies for small-scale CHP application of woody biomass are being developed by private companies in Central and Northern Finland. Some of these are presented in more detail. The technologies are either based on combustion or gasification of wood-based biomass. Using the product gas in combustion engines requires cleaning, which can be carried out with innovative dry or wet clearing processes. Dry cleaning is possible with catalysts and wet cleaning with scrubbers. The small-scale CHP technologies offer significant potential in local consumption sites of power and heat, such as greenhouses and farms. So called 'eco-villages' are also being built to demonstrate this potential. The possibilities for producing liquid transport fuels, such as biodiesel, are also discussed in this paper. (orig.)

  9. Secondary metabolism in simulated microgravity

    Science.gov (United States)

    Demain, A. L.; Fang, A.

    2001-01-01

    We have studied microbial secondary metabolism in a simulated microgravity (SMG) environment provided by NASA rotating-wall bioreactors (RWBs). These reactors were designed to simulate some aspects of actual microgravity that occur in space. Growth and product formation were observed in SMG in all cases studied, i.e., Bacillus brevis produced gramicidin S (GS), Streptomyces clavuligerus made beta-lactam antibiotics, Streptomyces hygroscopicus produced rapamycin, and Escherichia coli produced microcin B17 (MccB17). Of these processes, only GS production was unaffected by SMG; production of the other three products was inhibited. This was determined by comparison with performance in an RWB positioned in a different mode to provide a normal gravity (NG) environment. Carbon source repression by glycerol of the GS process, as observed in shaken flasks, was not observed in the RWBs, whether operated in the SMG or NG mode. The same phenomenon occurred in the case of MccB17 production, with respect to glucose repression. Thus, the negative effects of carbon source on GS and beta-lactam formation are presumably dependent on shear, turbulence, and/or vessel geometry, but not on gravity. Stimulatory effects of phosphate and the precursor L-lysine on beta-lactam antibiotic production, as observed in flasks, also occurred in SMG. An almost complete shift in the localization of produced MccB17 from cells to extracellular medium was observed when E. coli was grown in the RWB under SMG or NG. If a plastic bead was placed in the RWB, accumulation became cellular, as it is in shaken flasks, indicating that sheer stress favors a cellular location. In the case of rapamycin, the same type of shift was observed, but it was less dramatic, i.e., growth in the RWB under SMG shifted the distribution of produced rapamycin from 2/3 cellular:1/3 extracellular to 1/3 cellular:2/3 extracellular. Stress has been shown to induce or promote secondary metabolism in a number of other microbial

  10. Work environment stressors, social support, anxiety, and depression among secondary school teachers.

    Science.gov (United States)

    Mahan, Pamela L; Mahan, Michael P; Park, Na-Jin; Shelton, Christie; Brown, Kathleen C; Weaver, Michael T

    2010-05-01

    Work environment stress, a salient health and safety issue for secondary school teachers, school administrators, parents, and students, was examined in 168 teachers from two urban and five suburban high schools. The purpose of this study was to examine relationships between ongoing and episodic stressors and anxiety and depression, as well as the extent to which anxiety and depression may be predicted by stressors and coworker and supervisor support. The Ongoing Stressor Scale (OSS) and the Episodic Stressor Scale (ESS), the Coworker and Supervisor Contents of Communication Scales (COCS), the State Anxiety inventory (S-Anxiety), and the Center for Epidemiological Studies Depression Scale (CES-D) were used to measure the variables. Ongoing and episodic stressors were significantly and positively associated with anxiety and depression. Ongoing stressors and coworker support were significant in explaining anxiety and depression among secondary school teachers. Coworker support had an inverse relationship to anxiety and depression.

  11. Counseling For Entrepreneurship Development at Secondary ...

    African Journals Online (AJOL)

    The study focused on Counselling for Entrepreneurship Development at the Secondary School Level in Akwa Ibom State. The population comprised 705 principals of public and approved private secondary school in the State. A sample of 255 (116 male and 139 female) principals was drawn, using the stratified sampling ...

  12. Assessment Practices of Secondary Music Teachers

    Science.gov (United States)

    Russell, Joshua A.; Austin, James R.

    2010-01-01

    The purpose of this study was to survey assessment and grading practices employed by secondary music teachers throughout the southwestern region of the United States. Three main research questions guided the study: (1) What types of school district frameworks and classroom contexts are secondary music teachers operating within? (2) Which specific…

  13. Mathematics Anxiety in Secondary School Students

    Science.gov (United States)

    Ng, Lay Keow

    2012-01-01

    The detrimental consequences of mathematics anxiety have repeatedly been evidenced empirically, yet little is known of its influence on secondary school students in Asia. This study thus examined its origins and impact on 294 secondary students in Singapore through interviews and surveys. Results revealed an average anxiety level of 44% and a…

  14. Emotional Intelligence and Leadership Success of Secondary ...

    African Journals Online (AJOL)

    This is an expost facto research designed to determine the influence of emotional intelligence on leadership success of secondary school principals in Rivers State of Nigeria. The population consisted 441 principals (243 in public and 198 in private) secondary schools in Rivers State. A sample of 208 principals drawn ...

  15. Creating Career Awareness Among Secondary School Students ...

    African Journals Online (AJOL)

    This paper discussed the need for creating career awareness among Secondary School Students through career fair Career selection is a critical issue for secondary school students who may not be aware of the existing occupations in the labour market. It is important that career information be made available to students ...

  16. Secondary School Administration in Anambra State Today ...

    African Journals Online (AJOL)

    The study, a descriptive survey research design was used to identify the challenges that impede secondary school administration today in Anambra State. The population of the study was all the 259 public secondary school principals in the state. Two research questions and two null hypotheses guided the study. A 20-item ...

  17. Efficacy of secondary isoniazid preventive therapy among ...

    African Journals Online (AJOL)

    Objective. To determine the efficacy of secondary preventive therapy against tuberculosis (TB) among goldminers working in South Africa. Design. An observational study. Methods. The incidence of recurrent TB was compared between two cohorts of HIV-infected miners: one cohort had received secondary preventive ...

  18. Developing Junior Secondary School Students' Reading ...

    African Journals Online (AJOL)

    The study investigated the impact of Story Telling and Story Retelling on Secondary School Students' Reading Comprehension and Written Composition performance. Two hundred and forty (240) Junior Secondary School Students from three selected schools in Pankshin Local Government Area of Plateau State were ...

  19. Secondary chondrosarcoma: Malignant transformation of pre ...

    African Journals Online (AJOL)

    Secondary chondrosarcoma is a malignant hyaline cartilage tumour originating from a cartilaginous precursor, either osteochondroma or enchondroma. We contrast two different cases of biopsy-proven secondary chondrosarcomas resulting from benign, pre-existing cartilaginous lesions – our aim is to contrast and ...

  20. Secondary aerosol production from agricultural gas precursors

    Science.gov (United States)

    Studies of air quality indicate that agricultural emissions may impact particulate mass concentrations through both primary and secondary processes. Increasing evidence from both laboratory and field work suggests that not only does ammonia produce secondary particulate matter, but some volatile org...

  1. Emission of Secondary Electrons from Solid Deuterium

    DEFF Research Database (Denmark)

    Sørensen, H.

    1975-01-01

    An experimental facility was built where films of solid deuterium of known thickness could be made and where they could be irradiated with pulsed beams of electrons (up to 3 keV) and light ions (up to 10 keV). Studies of secondary electron emission were made and the secondary electron emission...

  2. Secondary Products (Markets, Competition, and Technological Improvements)

    Science.gov (United States)

    Philip A. Araman

    1988-01-01

    Competitiveness, imports, exports, and technological improvements--these are issues facing secondary wood-product manufacturers. The major problems focus on increasing foreign imports and the inability of U.S. industries to repell the imports. How and where should we, as researchers, allocate our efforts to enhance the competitiveness of secondary forest industries in...

  3. Stem secondary growth of tundra shrubs

    DEFF Research Database (Denmark)

    Campioli, Matteo; Leblans, Niki; Michelsen, Anders

    2012-01-01

    Our knowledge of stem secondary growth of arctic shrubs (a key component of tundra net primary production, NPP) is very limited. Here, we investigated the impact of the physical elements of the environment on shrub secondary growth by comparing annual growth rates of model species from similar...

  4. Transcriptional regulatory network controlling secondary cell wall ...

    African Journals Online (AJOL)

    Secondary wall is an abundant component of plant biomass and has a potential to be a renewable resource of bioenergy and biomaterials. It is important to unravel the molecular mechanism underlying secondary wall formation and how it contributes to plant biomass production. In this review, we summarized the potential ...

  5. Examining Practice in Secondary Visual Arts Education

    Science.gov (United States)

    Mitchell, Donna Mathewson

    2015-01-01

    Teaching in secondary visual arts classrooms is complex and challenging work. While it is implicated in much research, the complexity of the lived experience of secondary visual arts teaching has rarely been the subject of sustained and synthesized research. In this paper, the potential of practice as a concept to examine and represent secondary…

  6. Secondary Teachers' Perceptions of Online Learning

    Science.gov (United States)

    Brown, Chris L.

    2016-01-01

    The purpose of this qualitative study was to describe secondary teachers' perceptions of online learning in Washington. This was done by distributing a survey to three districts in the State of Washington to identify the advantages and challenges of online learning according to participating secondary teachers. In addition, the teachers provided…

  7. Patient satisfaction towards dental services among secondary ...

    African Journals Online (AJOL)

    Aim: To assess patient satisfaction on dental services among secondary school students. Design: Cross-sectional study. Study participants: 200 Secondary school students in Makambako township randomly selected from school class registers. Methods: Self-administered structured questionnaire in a class room. Reliability ...

  8. Influence Of Specialized Mathematical Language On Secondary ...

    African Journals Online (AJOL)

    Secondary school students in Kenya have continued to perform poorly in mathematics at the Kenya Certificate of Secondary Education (KCSE) national examinations. This continues to raise concern for all stakeholders in education due to the importance they attach to mathematics, a subject that is compulsory for all ...

  9. Record Management in Nigerian Secondary School Administration

    Science.gov (United States)

    Nakpodia, E. D.

    2009-01-01

    This paper examined the usefulness of record management in Nigerian Secondary Schools. Record keeping is one of the administrative principles in secondary school administration and it cannot be overemphasized in any organisation. The continuity of any school organisation depends on availability of useful records of past activities. In a complex…

  10. Assessing Participation in Secondary Education Quality ...

    African Journals Online (AJOL)

    The study examined some factors responsible for low participation of teachers, parents and communities in quality enhancement of secondary education in Cross River State, Nigeria. Teachers and parents of students in public secondary schools were used. A total of 8,590 subjects constituted the population of the study.

  11. Secondary island formation in collisional and collisionless kinetic simulations of magnetic reconnection

    Energy Technology Data Exchange (ETDEWEB)

    Dayton, William S [Los Alamos National Laboratory; Roytershteyn, Vadim [Los Alamos National Laboratory; Gary, Peter [Los Alamos National Laboratory; Yin, L [Los Alamos National Laboratory; Albright, B J [Los Alamos National Laboratory; Bowers, K J [Los Alamos National Laboratory; Karimabadi, H [UCSD

    2009-01-01

    The evolution of magnetic reconnection in large-scale systems often gives rise to extended current layers that are unstable to the formation of secondary magnetic islands. The role of these islands in the reconnection process and the conditions under which they form remains a subject of debate. In this work, we benchmark two different kinetic particle-in-cell codes to address the formation of secondary islands for several types of global boundary conditions. The influence on reconnection is examined for a range of conditions and collisionality limits. Although secondary islands are observed in all cases, their influence on reconnection may be different depending on the regime. In the collisional limit, the secondary islands playa key role in breaking away from the Sweet-Parker scaling and enabling faster reconnection. In the collisionless limit, their formation is one mechanism for controlling the length of the diffusion region. In both limits, the onset of secondary islands leads to a time dependent behavior in the reconnection rate. In all cases considered, the number of secondary islands increases for larger systems.

  12. On the Attitude of Secondary 1 Students towards Science

    Science.gov (United States)

    Kuppan, L.; Munirah, S. K.; Foong, S. K.; Yeung, A. S.

    2010-07-01

    The understanding of students' attitude towards science will give a sense of direction when designing pedagogical approaches and lesson packages so that reasons for not liking science is arrested and eventually the nation's need for science oriented workforce is addressed in the future. This study is part of a 3-year research project entitled PbI1@School: A large scale study on the effect of "Physics by Inquiry" pedagogy on Secondary One students' attitude and aptitude in science, involving school, National Institute of Education (NIE) Singapore, University of Washington at Seattle and the Ministry of Education (MOE) of Singapore. The results from a survey conducted on a sample size of 215 secondary 1 students indicate that fun in studying science is a major reason for their interest towards the subject. Those who do not like science dislike the idea of surface learning such as memorizing facts and information. Besides, all these students in our sample appear to be inquisitive. We believe that the teaching and learning system needs to be modified to increase or at least sustain the students' interest in science and capitalize on students' inquisitiveness. Although the results obtained are interesting and give an insight on secondary 1 students' attitude towards science, we intend to carry out a more rigorous study to identify correlations between students' responses for different attitude questions to understand deeply their attitude towards science.

  13. Metabolomic tools for secondary metabolite discovery from marine microbial symbionts.

    Science.gov (United States)

    Macintyre, Lynsey; Zhang, Tong; Viegelmann, Christina; Martinez, Ignacio Juarez; Cheng, Cheng; Dowdells, Catherine; Abdelmohsen, Usama Ramadam; Gernert, Christine; Hentschel, Ute; Edrada-Ebel, RuAngelie

    2014-06-05

    Marine invertebrate-associated symbiotic bacteria produce a plethora of novel secondary metabolites which may be structurally unique with interesting pharmacological properties. Selection of strains usually relies on literature searching, genetic screening and bioactivity results, often without considering the chemical novelty and abundance of secondary metabolites being produced by the microorganism until the time-consuming bioassay-guided isolation stages. To fast track the selection process, metabolomic tools were used to aid strain selection by investigating differences in the chemical profiles of 77 bacterial extracts isolated from cold water marine invertebrates from Orkney, Scotland using liquid chromatography-high resolution mass spectrometry (LC-HRMS) and nuclear magnetic resonance (NMR) spectroscopy. Following mass spectrometric analysis and dereplication using an Excel macro developed in-house, principal component analysis (PCA) was employed to differentiate the bacterial strains based on their chemical profiles. NMR 1H and correlation spectroscopy (COSY) were also employed to obtain a chemical fingerprint of each bacterial strain and to confirm the presence of functional groups and spin systems. These results were then combined with taxonomic identification and bioassay screening data to identify three bacterial strains, namely Bacillus sp. 4117, Rhodococcus sp. ZS402 and Vibrio splendidus strain LGP32, to prioritize for scale-up based on their chemically interesting secondary metabolomes, established through dereplication and interesting bioactivities, determined from bioassay screening.

  14. Metabolomic Tools for Secondary Metabolite Discovery from Marine Microbial Symbionts

    Directory of Open Access Journals (Sweden)

    Lynsey Macintyre

    2014-06-01

    Full Text Available Marine invertebrate-associated symbiotic bacteria produce a plethora of novel secondary metabolites which may be structurally unique with interesting pharmacological properties. Selection of strains usually relies on literature searching, genetic screening and bioactivity results, often without considering the chemical novelty and abundance of secondary metabolites being produced by the microorganism until the time-consuming bioassay-guided isolation stages. To fast track the selection process, metabolomic tools were used to aid strain selection by investigating differences in the chemical profiles of 77 bacterial extracts isolated from cold water marine invertebrates from Orkney, Scotland using liquid chromatography-high resolution mass spectrometry (LC-HRMS and nuclear magnetic resonance (NMR spectroscopy. Following mass spectrometric analysis and dereplication using an Excel macro developed in-house, principal component analysis (PCA was employed to differentiate the bacterial strains based on their chemical profiles. NMR 1H and correlation spectroscopy (COSY were also employed to obtain a chemical fingerprint of each bacterial strain and to confirm the presence of functional groups and spin systems. These results were then combined with taxonomic identification and bioassay screening data to identify three bacterial strains, namely Bacillus sp. 4117, Rhodococcus sp. ZS402 and Vibrio splendidus strain LGP32, to prioritize for scale-up based on their chemically interesting secondary metabolomes, established through dereplication and interesting bioactivities, determined from bioassay screening.

  15. To the problem of the secondary CMB anisotropy separation

    Directory of Open Access Journals (Sweden)

    Verkhodanov Oleg

    2016-01-01

    Full Text Available We study contribution to the secondary anisotropy maps of cosmic microwave background (CMB radiation which difficult to account for faint sources. Two effects are investigated. They are the Sunyaev–Zeldovich effect connected with the inverse Compton scattering of CMB photons on hot electrons of cluster of galaxies, and contamination of the background by weak extragalctic sources. First, we study fields of the Planck CMB maps around radio sources of the RATAN-600 catalog. We see weak microwave sources which make an additional contribution to the secondary anisotropy on angular small scales (< 7′. An algorithm for selecting candidate objects with the Sunyaev–Zeldovich effect was proposed, based on the use of data on the radio spectral indices and the signal in cosmic-microwave background maps. Second, applying the stacking method, we examine the areas of the CMB maps, constructed according to the Planck Space Observatory data in the neighborhood of different populations of radio sources and giant elliptical galaxies. The samples of objects include giant radio galaxies (GRG, radio sources, selected by the radio spectral index and redshift, as well as the gammaray bursts, used as a secondary comparative sample. The signal from this objects exists on CMB maps and its difference in the neighborhood of GRGs from the other types of objects was discovered.

  16. A Comminution Model for Secondary Fragmentation Assessment for Block Caving

    Science.gov (United States)

    Gómez, René; Castro, Raúl L.; Casali, Aldo; Palma, Sergio; Hekmat, Asieh

    2017-11-01

    Predicting the rock fragmentation obtained in drawpoints or secondary fragmentation is crucial in Block caving application since many engineering decisions are based on this key variable. These can include drawpoints size and spacing, equipment selection; draw control procedures, production rates, dilution entry and operational blasting requirements. Secondary fragmentation depends on several variables including structures, rock mass strength, the vertical pressure acting on the column, the rate of draw, and the height of the ore column. In order to study these variables, 18 experiments on gravity flow under confinement were run to quantify the fragmentation occurring in a draw column. Based on these experiments, a mathematical model was developed the basis of which considers a modified comminution model fitted using the experimental data. Finally, the fitted model was scaled up to represent what is expected to occur in practice compared to field data with an estimated accuracy of around 1.5% of size distributions. An approximation of the secondary fragmentation expected as a function of draw height and vertical pressure, for example for 400 m of ore column (mean vertical pressure of 4.2 MPa), the mean size, d 50, could decrease from 0.82 to 0.47 m and the large size, d 80, from 1.08 to 0.62 m.

  17. Occupational Stress and Job Satisfaction Among Indian Secondary School Teachers

    Directory of Open Access Journals (Sweden)

    Tahira Khatoon

    2015-06-01

    Full Text Available In this paper, empirical evidence on the differences in the occupational stress among teachers of secondary schools in Uttar Pradesh (U.P., India with respect to job satisfaction are provided. The population for the study consisted of 608 teachers, chosen from 41 schools of Eastern and Western districts in U.P. The Teachers Occupational Stress Scale (TOSS and Teachers Job Satisfaction Scale (TJSS were employed for the data collection, while the correlation techniques, analysis of variance, and t-test were used for statistical analysis. This study gives ample evidence that in secondary schools the majority of teachers face less stress towards their occupation than?. Male teachers exhibited more occupational stress towards their job as compared to females. This study validates the finding that teachers, in general, were moderately satisfied with their job; females enjoyed more satisfaction in their job than their male colleagues. The results of the analysis confirmed a negative correlation (r= -0.81 of occupational stress with teachers’ job satisfaction. Moreover, the results clearly show that as the job satisfaction of the teachers’ increased, their occupational stress decreased, accordingly. Teachers with high occupational stress levels were less satisfied, as compared to moderate and more satisfied, and there were no major differences in both the teachers in the less, moderate and more job satisfaction groups, regarding their occupational stress.

  18. Systems biology and biotechnology of Streptomyces species for the production of secondary metabolites

    DEFF Research Database (Denmark)

    Hwang, Kyu-Sang; Kim, Hyun Uk; Charusanti, Pep

    2014-01-01

    Streptomyces species continue to attract attention as a source of novel medicinal compounds. Despite a long history of studies on these microorganisms, they still have many biochemical mysteries to be elucidated. Investigations of novel secondary metabolites and their biosynthetic gene clusters...... have been more systematized with high-throughput techniques through inspections of correlations among components of the primary and secondary metabolisms at the genome scale. Moreover, up-to-date information on the genome of Streptomyces species with emphasis on their secondary metabolism has been...... collected in the form of databases and knowledgebases, providing predictive information and enabling one to explore experimentally unrecognized biological spaces of secondary metabolism. Herein, we review recent trends in the systems biology and biotechnology of Streptomyces species....

  19. Phylogenomic analysis of secondary metabolism genes sheds light on their evolution in Aspergilli

    DEFF Research Database (Denmark)

    Theobald, Sebastian; Vesth, Tammi Camilla; Rasmussen, Jane Lind Nybo

    thereof, find possible common ancestors and detect horizontal gene transfer events.Finally, we have performed large scale analysis of gene cluster dynamics and evolution, which provides us with better understanding of speciation in Aspergilli. With this new insights into the evolution of natural products.......Natural products are encoded by genes located in close proximity, called secondary metabolic gene clusters, which makes them interesting targets for genomic analysis. We use a modified version of the Secondary Metabolite Unique Regions Finder (SMURF) algorithm, combined with InterPro annotations to create...... approximate maximum likelihood trees of conserved domains from secondary metabolic genes across 56 species, giving insights into the secondary metabolism gene diversity and evolution.In this study we can describe the evolution of non ribosomal peptide synthetases (NRPS), polyketide synthases (PKS) and hybrids...

  20. Mathematics Anxiety and Attitudes of Secondary School Students in Rural Area: A Correlational Research

    Directory of Open Access Journals (Sweden)

    Engin Karadağ

    2014-12-01

    Full Text Available Correlation between mathematics anxiety and attitude of children who are educated in rural areas were analyzed in this research. Research was premeditated as a correlational design because it was presumed that there was correlation between two main variables. The population of the study was consisted of secondary school students who were educated in a region called rural areas in the central district of Meram/Konya in the school year of 2012-2013. 726 students who were educated in five secondary schools comprised of research sample which was designated as stratified sampling method according to educational regions. Research data were collected by the Mathematics Anxiety Scale, and Mathematics Attitude Scale. Correlation and multiple regression analyses were used to examine data. Findings show that correlation between anxiety and attitude of secondary school students from rural area is in negative direction.Key Words:    Rural education, mathematics attitude, mathematics anxiety

  1. Scaling of Metabolic Scaling within Physical Limits

    Directory of Open Access Journals (Sweden)

    Douglas S. Glazier

    2014-10-01

    Full Text Available Both the slope and elevation of scaling relationships between log metabolic rate and log body size vary taxonomically and in relation to physiological or developmental state, ecological lifestyle and environmental conditions. Here I discuss how the recently proposed metabolic-level boundaries hypothesis (MLBH provides a useful conceptual framework for explaining and predicting much, but not all of this variation. This hypothesis is based on three major assumptions: (1 various processes related to body volume and surface area exert state-dependent effects on the scaling slope for metabolic rate in relation to body mass; (2 the elevation and slope of metabolic scaling relationships are linked; and (3 both intrinsic (anatomical, biochemical and physiological and extrinsic (ecological factors can affect metabolic scaling. According to the MLBH, the diversity of metabolic scaling relationships occurs within physical boundary limits related to body volume and surface area. Within these limits, specific metabolic scaling slopes can be predicted from the metabolic level (or scaling elevation of a species or group of species. In essence, metabolic scaling itself scales with metabolic level, which is in turn contingent on various intrinsic and extrinsic conditions operating in physiological or evolutionary time. The MLBH represents a “meta-mechanism” or collection of multiple, specific mechanisms that have contingent, state-dependent effects. As such, the MLBH is Darwinian in approach (the theory of natural selection is also meta-mechanistic, in contrast to currently influential metabolic scaling theory that is Newtonian in approach (i.e., based on unitary deterministic laws. Furthermore, the MLBH can be viewed as part of a more general theory that includes other mechanisms that may also affect metabolic scaling.

  2. Psychometric properties of the Questionnaire for Secondary Traumatization

    Directory of Open Access Journals (Sweden)

    Katharina Weitkamp

    2014-01-01

    Full Text Available Background: During the past several years, there has been a growing interest in the negative effects that providing therapy may have on therapists. Of special interest is a phenomenon called secondary traumatization, which can arise while working with traumatized clients. To develop a simple screening tool for secondary traumatization, a quantitative assessment instrument was constructed using a data-driven approach based on qualitative interviews with affected trauma therapists as well as experienced supervisors in trauma therapy. Objective: The aim of the current study was to analyze the psychometric properties of the newly developed Questionnaire for Secondary Traumatization (FST acute and lifetime version and to determine the most appropriate scoring procedure. Method: To this end, three independent samples of psychotherapists (n=371, trauma therapists in training (n=80, and refugee counselors (n=197 filled out an online questionnaire battery. Data structure was analyzed using factor analyses, cluster analyses, and reliability analyses. Results: Factor analyses yielded a six-factor structure for both the acute and the lifetime version with only a small number of items loading on differing factors. Cluster analyses suggested a single scale structure of the questionnaire. The FST total score showed good internal consistencies across all three samples, while internal consistency of the six extracted factors was mixed. Conclusion: With the FST, a reliable screening instrument for acute and lifetime secondary traumatization is now available which is free of charge and yields a sum score for quick evaluation. The six-factor structure needs to be verified with confirmatory factor analyses.

  3. Secondary traumatic stress among emergency nurses: a cross-sectional study.

    Science.gov (United States)

    Duffy, Emer; Avalos, Gloria; Dowling, Maura

    2015-04-01

    Emergency department nurses are required to deal with emotional trauma issues on a daily basis, which may result in them experiencing symptoms of secondary traumatic stress, a consequence of stress experienced when helping or wanting to help a person traumatised or suffering. This study measured emergency department nurses' self-reported levels of secondary traumatic stress. Registered nurses (n = 117) working at three emergency departments in the Western geographical region of Ireland were invited to complete the secondary traumatic stress scale (STSS). A response rate of 90% (n = 105) was achieved. Most participants (n = 67/64%) met the criteria for secondary traumatic stress. A statistically significant finding was that the highest proportion (82%) of secondary traumatic stress existed in the staff nurse group (p = 0.042). Moreover, for those nurses reporting secondary traumatic stress, statistical significance was found for the variables 'change of career considered' (p = 0.017) and 'finds alcohol helpful in alleviating work-related stress' (p = 0.004), when compared with nurses not reporting secondary traumatic stress. The findings suggest the need to examine current crisis management interventions and to introduce new systems to support nurses in Irish emergency departments. Moreover, because different types of traumatic events in the ED require different types of interventions, the prevention and management of STS among emergency department nurses must be tackled using a variety of approaches. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Triangulating Teacher Perception, Classroom Observations, and Student Work to Evaluate Secondary Writing Programs

    Science.gov (United States)

    Henderson, Daphne Carr; Rupley, William H.; Nichols, Janet Alys; Nichols, William Dee; Rasinski, Timothy V.

    2018-01-01

    Current professional development efforts in writing at the secondary level have not resulted in student improvement on large-scale writing assessments. To maximize funding resources and instructional time, school leaders need a way to determine professional development content for writing teachers that aligns with specific student outcomes. The…

  5. Case Series of Mania Secondary to HIV/AIDS in Patients at two ...

    African Journals Online (AJOL)

    Case Series of Mania Secondary to HIV/AIDS in Patients at two Tertiary Hospitals in Lusaka, Zambia. ... The Young Mania Rating Scale scores were calculated at the time of recruitment and at the time of follow up at 4 weeks and at 8 weeks after discharge. The mean YMRS at the time of follow up (8weeks) was zero while ...

  6. Oral Reading Fluency as a Predictor of Silent Reading Fluency at Secondary and Postsecondary Levels

    Science.gov (United States)

    Seok, Soonhwa; DaCosta, Boaventura

    2014-01-01

    This research investigated oral reading fluency as a predictor of silent reading fluency at the secondary and postsecondary levels. Several measures were used, including the Gray Oral Reading Test, the Test of Silent Word Reading Fluency, the Test of Silent Contextual Reading Fluency, and the Reading Observation Scale. A total of 223 students…

  7. Teachers' Perceptions of the Teaching of Acids and Bases in Swedish Upper Secondary Schools

    Science.gov (United States)

    Drechsler, Michal; Van Driel, Jan

    2009-01-01

    We report in this paper on a study of chemistry teachers' perceptions of their teaching in upper secondary schools in Sweden, regarding models of acids and bases, especially the Bronsted and the Arrhenius model. A questionnaire consisting of a Likert-type scale was developed, which focused on teachers' knowledge of different models, knowledge of…

  8. Life skills training as HIV/AIDS preventive strategy in secondary ...

    African Journals Online (AJOL)

    Life skills training as HIV/AIDS preventive strategy in secondary schools: evaluation of a large-scale implementation process. ... The implementation of the intervention was evaluated in 24 schools in two educational districts in Gauteng province using an action research approach. Data about the implementation were ...

  9. Who Will Stay and Who Will Leave? Predicting Secondary English Teacher Attrition Risk

    Science.gov (United States)

    Hancock, Carl B.; Scherff, Lisa

    2010-01-01

    Although there are considerable large-scale data on teacher attrition, few researchers have culled information specifically related to English teachers' risk for attrition. This study examines the effects of teacher characteristics, teaching conditions, student variables, self-efficacy, external support, and salary on secondary English language…

  10. Supplying Disadvantaged Schools with Effective Teachers: Experimental Evidence on Secondary Math Teachers from Teach For America

    Science.gov (United States)

    Chiang, Hanley S.; Clark, Melissa A.; McConnell, Sheena

    2017-01-01

    Teach For America (TFA) is an important but controversial source of teachers for hard-to-staff subjects in high-poverty U.S. schools. We present findings from the first large-scale experimental study of secondary math teachers from TFA. We find that TFA teachers are more effective than other math teachers in the same schools, increasing student…

  11. Extensive Reading in EFL Classroom at Secondary Schools in Bangladesh: Current Practices and Future Possibilities

    Science.gov (United States)

    Haider, Md. Zulfeqar; Akhter, Elina

    2012-01-01

    Extensive reading is being practiced in many EFL and ESL classrooms as an effective means for developing learners' reading as well as other related skills. This paper is based on a small-scale study that explores the current practices and future possibilities of using extensive reading in the EFL classrooms at the junior secondary schools in…

  12. Dropout in the lower tracks of Dutch secondary education : Predictor variables and variation among schools

    NARCIS (Netherlands)

    Luyten, H; Bosker, R.J.; Dekkers, H; Derks, A

    2003-01-01

    This study analyses the data from a large-scale longitudinal investigation into the effect of both school and student characteristics on the dropout rate for students in lower secondary education in The Netherlands. Dropout rates were found to vary significantly between schools, but only a single

  13. Psychometric properties of the aggression questionnaire in Dutch violent forensic psychiatric patients and secondary vocational students.

    NARCIS (Netherlands)

    Hornsveld, R.H.J.; Muris, P.; Kraaimaat, F.W.; Meesters, C.

    2009-01-01

    The psychometric properties of a Dutch version of Buss and Perry's Aggression Questionnaire (AQ) were examined in a sample of violent forensic psychiatric inpatients and outpatients and a sample of secondary vocational students. The internal consistency, interitem correlations, and item-scale

  14. The Effectiveness of Secondary Math Teachers from Teach For America and the Teaching Fellows Programs

    OpenAIRE

    Clark, Melissa A.; Hanley S. Chiang; Tim Silva; Sheena McConnell; Kathy Sonnenfeld; Anastasia Erbe; Michael Puma

    2013-01-01

    The first large-scale, random assignment study of the effects of secondary school math teachers from Teach For America and the Teaching Fellows programs found they were as effective as, and in some cases more effective than, teachers receiving traditional certification. The study was sponsored by the U.S. Department of Education's Institute of Education Sciences.

  15. An Investigation into Factors Contributing to Iranian Secondary School English Teachers' Job Satisfaction and Dissatisfaction

    Science.gov (United States)

    Soodmand Afshar, Hassan; Doosti, Mehdi

    2016-01-01

    This study explored factors contributing to job satisfaction and dissatisfaction of male and female Iranian secondary school English teachers. A Likert-scale 58-item questionnaire was developed which was completed by 210 participants. The questionnaire also included three open-ended questions which investigated participants' motivation and…

  16. An Analysis of the Relation between Secondary School Organizational Climate and Teacher Job Satisfaction

    Science.gov (United States)

    Xiaofu, Pan; Qiwen, Qin

    2007-01-01

    This study investigates and analyzes the relation between the secondary school organizational climate and teacher job satisfaction using a self-designed school organizational climate scale based on studies in China and abroad. The findings show that except for interpersonal factors there are significant correlations between the various factors of…

  17. Personality and Religion among Secondary School Pupils in the Czech Republic

    Science.gov (United States)

    Francis, Leslie J.; Quesnell, Michael; Lewis, Christopher A.

    2010-01-01

    The short-form Revised Eysenck Personality Questionnaire was completed by 1,780 boys and 1,634 girls attending secondary schools in the Czech Republic, together with the Francis Scale of Attitude towards Christianity. On the one hand, two of the findings are consistent with those from a series of studies employing the same measure of religiosity…

  18. Application of aging methods to estimate long term performance of secondary materials for road construction

    NARCIS (Netherlands)

    Akbarnejad, S.; Houben, L.J.M.; Molenaar, A.A.A.

    2012-01-01

    Long term performance of secondary materials is becoming a challenging aspect in road construction since due to their benefits they are being used on a large scale, but on the other hand their future behaviors are difficult to estimate. In this study, aging is proposed as a means of exploring the

  19. Search for Trustful Leadership in Secondary Schools: Is Empowerment the Solution?

    Science.gov (United States)

    Freire, Carla; Fernandes, António

    2016-01-01

    The purpose of this study is to analyse how the access to structures of empowerment by teachers in primary and secondary education impacts on their trust of the headmaster of the school management board. Using the theoretical framework of empowerment and trust in the context of companies, one adapted the constructs of these scales to the reality…

  20. Black Pineleaf Scale (FIDL)

    Science.gov (United States)

    Katharine A. Sheehan; Mario A. Melendez; Shana Westfall

    1998-01-01

    The black pineleaf scale (Nuculaspis californica (Coleman)) belongs to a group of sucking insects called armored scales. Concealed under their protective shells, these scales insert their mouthparts into their hosts, removing sap and, possibly, injecting toxic enzymes secreted in the saliva. Armored scales are important pests of agricultural and ornamental plants;...

  1. Principles for enabling deep secondary design

    DEFF Research Database (Denmark)

    Pries-Heje, Jan; Hansen, Magnus Rotvit Perlt

    2017-01-01

    design by analyzing two cases where secondary designers fundamentally change functionality, content and technology complexity level. The first case redesigns a decision model for agile development in an insurance company; the second creates a contingency model for choosing project management tools...... and techniques in a hospital. Our analysis of the two cases leads to the identification of four principles of design implementation that primary designers can apply to enable secondary design and four corresponding design implementation principles that secondary designers themselves need to apply....

  2. PARATHYROID CANCER OCCURRING IN RELAPSING SECONDARY HYPERPARATHYROIDISM

    Directory of Open Access Journals (Sweden)

    I. V. Kotova

    2016-01-01

    Full Text Available We present a clinical case of parathyroid cancer in a patient with relapsing secondary hyperparathyroidism at 4 years after subtotal parathyroidectomy. Its unique character is related to the combination of relapsing secondary hyperparathyroidism, parathyromatosis, ectopic of an adenomatous hyperplastic parathyroid gland into the thyroid gland, and parathyroid cancer. Several most complicated aspects of parathyroid surgery are disclosed, such as the choice of strategy for surgical intervention in secondary hyperparathyroidism, complexity of morphological and cytological diagnostics of this disorder.

  3. Secondary missile injury from lightning strike.

    Science.gov (United States)

    Blumenthal, Ryan

    2012-03-01

    A 48-year-old-woman was struck dead by lightning on October 24, 2010, in Pretoria, South Africa. The cause of death was due to direct lightning strike. Examination showed secondary missile injury on her legs. This secondary missile (shrapnel) injury was caused by the lightning striking the concrete pavement next to her. Small pieces of concrete were located embedded within the shrapnel wounds. This case report represents the first documented case of secondary missile formation (shrapnel injury) due to lightning strike in the literature.

  4. Double-Barred Galaxies: I. A Catalog of Barred Galaxies with Stellar Secondary Bars and Inner Disks

    OpenAIRE

    Erwin, Peter

    2003-01-01

    I present a catalog of 67 barred galaxies which contain distinct, elliptical stellar structures inside their bars. Fifty of these are double-barred galaxies: a small-scale, "inner" or "secondary" bar is embedded within a large-scale, "outer" or "primary" bar. I provide homogenized measurements of the sizes, ellipticities, and orientations of both inner and outer bars, along with with global parameters for the galaxies. The other 17 are classified as "inner-disk" galaxies, where a large-scale ...

  5. Secondary ledeburite formation during various welding techniques

    Directory of Open Access Journals (Sweden)

    Tonkovič M.P.

    2015-01-01

    Full Text Available The occurrence and formation sequence of secondary ledeburite in the heat affected zone of chromium ledeburitic tool steel W.Nr. 1.2379 (OCR12 VM after welding with SAW, TIG, microplasma and laser welding techniques is presented in this paper. Special attention was paid on the behaviour of carbides. The occurrence of secondary ledeburite is a result of local enrichment of the austenite matrix with alloying elements, due to partial or complete dissolution of primary/eutectic carbides. The results show that the largest amount of secondary ledeburite is formed during submerged arc welding, followed by TIG and microplasma welding technique. Welding by laser technique, with appropriate technological parameters, could prevent secondary ledeburite formation.

  6. Secondary Amenorrhea among Female Athletes. Current Understandings.

    Science.gov (United States)

    Sasiene, Gwen Hagenbuch

    1983-01-01

    Research pertaining to female athletes' problems with secondary amenorrhea is reviewed. Studies point to stress, weight loss, anorexia nervosa, obesity, arduous athletic training, and age of onset of training as factors which may contribute to this disorder. (PP)

  7. Predicting Thermal Behavior of Secondary Organic Aerosols

    Data.gov (United States)

    U.S. Environmental Protection Agency — Volume concentrations of secondary organic aerosol (SOA) are measured in 139 steady-state, single precursor hydrocarbon oxidation experiments after passing through a...

  8. Study of Secondary Emission Enhanced Photoinjector

    CERN Document Server

    Chang, Xiangyun; Burrill, Andrew; Johnson, Peter; Kewisch, Jorg; Rao, Triveni; Segalov, Zvi; Zhao, Yongxiang

    2005-01-01

    The secondary emission enhanced photoinjector (SEEP) is a very promising new approach to the generation of high-current, high-brightness electron beams. Primary electrons with a few thousand electron-volts of energy strike a specially prepared diamond window. The large Secondary Electron Yield (SEY) provides a multiplication of the number of electrons by about two orders of magnitude. The secondary electrons drift through the diamond under an electric field and emerge into the accelerating proper of the “gun” through a Negative Electron Affinity (NEA) surface of the diamond (Hydrogen terminated). We present the calculation of heating power sources and the temperature distribution in details. Some properties of the secondary electron beam related to beam dynamics are also reported. The results show feasibility of this kind of cathode.

  9. Sexual Behaviour and Practices Among Secondary School ...

    African Journals Online (AJOL)

    60) and monetary gains 27.5% (33). Conclusion: Risky sexual behaviour is high among this age group. Efforts to promote sexuality education and contraceptive awareness should be intensified. Key words: sexual behaviour, secondary schools,

  10. Prevalence Of Cigarette Smoking Behaviour Among Secondary ...

    African Journals Online (AJOL)

    based factors in determining truancy behaviour among secondary school adolescents in Ijebu-ode, Ogun State, Nigeria. A survey research design was adopted, and three hypotheses were generated and tested in the study. Two hundred and ...

  11. Secondary and College LD Bypass Strategies.

    Science.gov (United States)

    Mosby, Robert J.

    1981-01-01

    The author describes the Developmental By-Pass (DBP) Instructional technology for teaching secondary and college learning disabled (LD) students by allowing students to bypass ordering and organizational deficits. (SB)

  12. Regulation and Role of Fungal Secondary Metabolites.

    Science.gov (United States)

    Macheleidt, Juliane; Mattern, Derek J; Fischer, Juliane; Netzker, Tina; Weber, Jakob; Schroeckh, Volker; Valiante, Vito; Brakhage, Axel A

    2016-11-23

    Fungi have the capability to produce a tremendous number of so-called secondary metabolites, which possess a multitude of functions, e.g., communication signals during coexistence with other microorganisms, virulence factors during pathogenic interactions with plants and animals, and in medical applications. Therefore, research on this topic has intensified significantly during the past 10 years and thus knowledge of regulatory mechanisms and the understanding of the role of secondary metabolites have drastically increased. This review aims to depict the complexity of all the regulatory elements involved in controlling the expression of secondary metabolite gene clusters, ranging from epigenetic control and signal transduction pathways to global and specific transcriptional regulators. Furthermore, we give a short overview on the role of secondary metabolites, focusing on the interaction with other microorganisms in the environment as well as on pathogenic relationships.

  13. Holocaust Denial among Slovenian Secondary School Pupils

    Directory of Open Access Journals (Sweden)

    Maša Pavlič

    2015-06-01

    Full Text Available The article presents tendencies of Holocaust denial among secondary school pupils in Slovenia. It focuses on research implemented in January 2012, in which 400 Slovenian secondary school pupils were included. In spite of the assumption that Holocaust denial amongst the youth in Slovenia already exists, we also assumed that a degree of Holocaust denial amongs Slovenian pupils is lower that amongst their peers in other EU countries. Research also inquired about the level of anti-Semitism in conjunction with Holocaust denial. The research project confirmed that students on lower levels of high school education and with less history and sociology lessons in curriculum are more receptive for the Holocaust denial and anti-Semitism is more present in this demographic. The level of Holocaust denial amongst secondary school pupils is not negligible; it suggests that this topic should be more thoroughly discussed in secondary schools.

  14. Sensitization of Secondary School Students towards Sustainable ...

    African Journals Online (AJOL)

    gold

    2012-07-26

    Jul 26, 2012 ... Sensitization of Secondary School Students towards. Sustainable Electoral Process in Nigeria: Nigeria. Independent Electoral Commission as a Focus. (Pp. 239-251). Uhunmwuangho, Sunday Okungbowa - Lecturer, Institute of Public. Administration & Extension Services, University of Benin, Benin City,.

  15. Intensive Blood Pressure Reduction and Spot Sign in Intracerebral Hemorrhage: A Secondary Analysis of a Randomized Clinical Trial.

    Science.gov (United States)

    Morotti, Andrea; Brouwers, H Bart; Romero, Javier M; Jessel, Michael J; Vashkevich, Anastasia; Schwab, Kristin; Afzal, Mohammad Rauf; Cassarly, Christy; Greenberg, Steven M; Martin, Renee Hebert; Qureshi, Adnan I; Rosand, Jonathan; Goldstein, Joshua N

    2017-08-01

    The computed tomographic angiography (CTA) spot sign is associated with intracerebral hemorrhage (ICH) expansion and may mark those patients most likely to benefit from intensive blood pressure (BP) reduction. To investigate whether the spot sign is associated with ICH expansion across a wide range of centers and whether intensive BP reduction decreases hematoma expansion and improves outcome in patients with ICH and a spot sign. SCORE-IT (Spot Sign Score in Restricting ICH Growth) is a preplanned prospective observational study nested in the Antihypertensive Treatment of Acute Cerebral Hemorrhage II (ATACH-II) randomized clinical trial. Participants included consecutive patients with primary ICH who underwent a CTA within 8 hours from onset at 59 sites from May 15, 2011, through December 19, 2015. Data were analyzed for the present study from July 1 to August 31, 2016. Patients in ATACH-II were randomized to intensive (systolic BP target, sign, and 24 of 123 without missing data (19.5%) experienced ICH expansion. The spot sign was associated with expansion with sensitivity of 0.54 (95% CI, 0.34-0.74) and specificity of 0.63 (95% CI, 0.53-0.72). After adjustment for potential confounders, intensive BP treatment was not associated with a significant reduction of ICH expansion (relative risk, 0.83; 95% CI, 0.27-2.51; P = .74) or improved outcome (relative risk of 90-day modified Rankin Scale score ≥4, 1.24; 95% CI, 0.53-2.91; P = .62) in spot sign-positive patients. The predictive performance of the spot sign for ICH expansion was lower than in prior reports from single-center studies. No evidence suggested that patients with ICH and a spot sign specifically benefit from intensive BP reduction. clinicaltrials.gov Identifier: NCT01176565.

  16. Bionics in secondary school's physics curriculum

    OpenAIRE

    Poplavskis, Jānis

    2013-01-01

    Annotation The task of the promotional work "Bionics in secondary school's physics curriculum" - to view the secondary school's physics curriculum, the possibility to involve bionics in physics learning process, to develop a didactical model that integrates the student's knowledge and promotes the development of technological competence and facilitates the growth of interest towards natural sciences. Analysis of literature and educational documentation of the pedagogical and psychological asp...

  17. Perforation of the palate in secondary syphilis

    Directory of Open Access Journals (Sweden)

    Pavithran K

    1994-01-01

    Full Text Available A middle aged woman with secondary syphilis-diagnosed clinically and serologically was prescribed oral tetracyline. She did not complete the course of treatment. Recurrent mucosal erosions in the mouth she developed subsequently as manifestation of relapsing secondary syphilis were wrongly diagnosed as ′aphthous stomatitis′ and were treated with betamethasone gargling. The erosions progressed to ulcerations and finally resulted in perforation of the soft palate.

  18. Debriefing Note Secondary Education Support Programme

    DEFF Research Database (Denmark)

    Webster, Neil; Vagnby, Bo Hellisen; Thomsen, Thomas J.

    Debriefing note regarding joint programming for the Secondary Education Support Programme (2003- 2007). The note specifies preparation of SIP Physical Guidelines; Training needs assessment for Physical School Status and Rapid Technical Assessments; SIP/DEP preparation; Selection criteria for dist......Debriefing note regarding joint programming for the Secondary Education Support Programme (2003- 2007). The note specifies preparation of SIP Physical Guidelines; Training needs assessment for Physical School Status and Rapid Technical Assessments; SIP/DEP preparation; Selection criteria...

  19. Learning Styles of Students of Secondary Schools

    OpenAIRE

    Chocholoušová, Michaela

    2013-01-01

    This thesis is focused on learning styles of students of secondary schools, particularly of secondary vocational schools. It is divided in two parts - theoretical and practical. The theoretical part deals with the definitions of basic terms as learning, learner and meaningful learning. It also analysis the term learning style and other related terms, such as cognitive style. Final section of the theoretical part is dedicated to mesurement and influencing od leraning styles as a preparation fo...

  20. Student engagement in two Singaporean secondary schools

    OpenAIRE

    Tan, Yuen Teng

    2016-01-01

    Student engagement is important to prevent school dropout and enhance school experiences. Engagement of secondary 2 and 3 students in Singapore was studied with Student Engagement Instrument (SEI) and its relation to burnout. The SEI measured students’ cognitive and affective engagement while burnout was examined using School Burnout Inventory (SBI). An electronic survey was administered to 335 students from two secondary schools. The engagement and burnout across grades, streams, gender, aca...